1. Kentucky Derby (the first Saturday in May) and the Kentucky Derby Festival:
http://www.kentuckyderby.info/
http://www.choicehotels.com/ires/en-US/html/ThingsToDoEvent?event_id=157923

2. The Indianapolis 500, May 30 2010:
http://www.indy500.com/

3. New Orleans Jazz and Heritage Festival 2010 (April, May):
http://www.nojazzfest.com/
http://www.jazzandheritage.org/

"Over the years Jazz Fest has received many honors, including being named the Festival of the Year four times by Pollstar magazine. The 2004 event marks the 35th anniversary of Jazz Fest, which the Wall Street Journal says 'showcases a wider, deeper lineup of essential American musical styles than any festival in the nation…' and which Life magazine has called 'the country’s very best music festival.' "

4. Disney World Resort Events:
http://www.wdwnews.com/ViewPressRelease.aspx?PressReleaseID=113749

"In early 2010, Walt Disney World Resort will bloom with bursting color during the Epcot International Flower & Garden Festival; host 100 exemplary teens from across the country in a one-of-a-kind enrichment workshop; again host the Atlanta Braves on its “field of dreams” at ESPN Wide World of Sports Complex; and be the site for the 26 most magical miles on Earth during the annual Walt Disney World Marathon Weekend."

(Includes dates from March through May)

5. World Beer Festival:
http://www.allaboutbeer.com/wbfrichmond/index.html

"All About Beer Magazine announced today that the World Beer Festival scheduled for August 29 in Richmond will be held instead in the spring of 2010."

" 'We are committed to putting on a world-class event,' said Daniel Bradford, producer of the festival and publisher of All About Beer Magazine. 'Some of the preparations are taking longer than expected, and we need more time to ensure that the World Beer Festival Richmond meets its potential. The Richmond beer community is knowledgeable and enthusiastic, and the World Beer Festival has a unique role to play in enhancing that community.' "

6. Denver International Auto Show, April 2010:
http://www.biztradeshows.com/trade-events/denver-auto-show.html
http://www.paragonexpo.com/399.html

"The Denver Auto Show is bigger and better than ever! The car show is the perfect place to see the latest examples of fuel efficient technologies and aftermarket accessories. At the Colorado Convention Center you'll not only see all the new 2010 models, but also be treated to sneak peeks of selected 2011 intros, concepts and the latest in tricked out cars! "

7. 71st Senior PGA Championship, May 2010:
http://www.pga.com/seniorpga/2010/

"Don't miss out on the opportunity to witness history unfold in person when the 71st Senior PGA Championship is played at Colorado Golf Club outside Denver."

8. de Young Museum, San Fransisco special exhibits:
http://www.lovetoeatandtravel.com/site/sfbay/SF/Fun/park_de_young_exhibits.htm

"Tutankhamun and the Golden Age of the Pharoahs" (March)
"Birth of Impressionism: Masterpieces from the Musee d'Orsay" (May)

"The treasures of Tutankhamun return to San Francisco for the first time in 30 years."

"San Francisco is the ONLY city that will be displaying these exciting exhibitions, featuring some of the most brilliant works of Impressionist and Post-Impressionist art.
Famous paintings such as Renoir's "The Swing" and Whistler's "Whistler's Mother" are among the many masterpieces coming to San Francisco next year. Early works by Manet, Monet, Renoir and Sisley, and a selection of Degas paintings will also be on view."

9. Dollywood:
http://www.gatlinburgtnweather.com/seasonal_festivals_and_events.html

"Dollywood's Annual Festival of Nations with more than 250 international performers at this multicultural spring festival featuring musicians, dancers and artisans bringing a world of entertainment to the Great Smoky Mountains. March 27 - April 26, 2010."

(Also at the above link: 5th Annual Bloomin' BBQ & Bluegrass Festival, 29th Annual Gatlinburg Scottish Festival, Gatlin Fine Arts Festival, 7th Annual Smoky Mountain Springfest)

10. World Synchronized Skating Championships, April 9 & 10, 2010:
http://www.2010synchroworlds.com/

"U.S. Figure Skating introduced championship-caliber synchronized skating to the world when it hosted the inaugural World Synchronized Skating Championships in 2000. Ten years later, and stronger than ever, the World Synchronized Skating Championships return to the United States. Watch the best teams in the world battle it out for the most coveted title in the sport."

And just for kicks, here are a few links to some different ideas:

Coffee Fest New York at the Meadowlands:
http://www.coffeefest.com/

International Boston Seafood Show (largest in North America):
http://www.bostonseafood.com/09/public/enter.aspx

International Cheese Expo:
http://www.cheeseexpo.org/

"It is the world's largest gathering devoted solely to the multi-billion dollar market for cheese and related dairy products."

New York International Independent Film and Video Festival, Los Angeles location, Spring 2010:
http://www.nyfilmvideo.com/?gclid=CPO48q6Evp0CFRcjawodbzYQiA

"The festival is known as 'the voice for independent film' and receives extensive coverage in all major media. The NYIIFVF has received press coverage in: Variety, Hollywood Reporter, Fox 5, CNN, New York Observer, New York Times, Newsday, LA Times, LA Weekly, Time Out NY, E News, NY Daily News, Wall Street Journal, New York Post, Movie Maker, Star Magazine, Screentalk Magazine, to name a few. As indie guru Abel Ferrara famously quoted in an interview with Movie Maker, 'This festival is the real deal; everybody else just talks about doing it and these guys just do it.' "

1. SXSW. A music festival that's overrun with hipsters and music industry people trying to find the next big thing, it probably has the best collection of talent of all the American music festivals. And you don't have to stand in a muddy field! It's held in Austin, Texas, centered around the downtown convention center. The music part will be from March 17th to 21st this year, but you could go early on the 12th if you're interested in catching the film part of the festival. It's a couple hundred dollars for a ticket, but well worth it for anyone interested in music.

2. Coachella. If you like the big outdoors and don't mind the camping aspect, this festival might be even more appealing. Standing in the Californian desert squashed together with tons of other music lovers singing along to songs by universally loved artists can be an almost religious experience for some of the people who go. Featuring instillation art and sculptures scattered around the grounds, it resembles a modern musical mecca in a way. Names like Radiohead, The Cure, Pixies, Madonna, and The Jurassic 5 have all performed there. Definitely worth checking out.

3. March Madness, any of the final four games. The NCAA tournament is a hugely popular sporting event in America, mostly because everyone loves making their brackets and betting on who wins. But watching tons of basketball is definitely a part of it, too. Different colleges compete to see who can win this ultimate square off while the rest of America watches with bated breath to see if their bets will pay off.

4. Masters Tournament. From April 5th to 11th in 2010, you can watch some of the absolute masters of golf at the top of their game. The hushed crowds and slow pace may not be to everyone's liking, but the grounds themselves are beautiful even if golf isn't your sport of choice. But for any fanatics, this can be the highlight of the year.

5. Tribeca Film Festival. Founded in a response to the 9/11 attacks, this film festival is already one of the most influential. Many major movies, like Star Wars Episode II and Spiderman 3, premiered there. But for the most part, it's indie movies all the way. There's even a small set up for emerging musicians put on by ASCAP and family themed movies, so it'd be a wonderful event for the whole family.

6. San Francisco International Film Festival. If you want a more established, West Coast film festival, than the San Francisco International Film Festival is it. Running from April 22nd to May 6th, it's an amazingly intimate atmosphere for such a large festival. With a whole two weeks full of events, you can imagine that there's a huge variety of movies to pick from. There's literally something everyone can enjoy.

7. Anime Boston. Though completely nerdy and geeky, this gathering in early April to appreciate Japanese animation, comics, and pop culture is a sight to behold. People dress in incredibly detailed costumes the likes of which you only dreamed of getting to wear for Halloween as a kid. Even if you're not a fan of anime, after a visit to this convention, you might have a change of heart.

8. Shenandoah Apple Blossom Festival. It may seem quaint in comparison to some of the other events on the list, but I don't think the hosting town of Winchester, Virginia minds too much. This year it runs from April 23rd to May 2nd. It's about as traditional Americana you can get with as many as 250,000 visitors. There's apple pie baking contests, dances, lunches, carnival midways and rides, wine tasting, golf, concerts, races, a circus, and a crowning of Queen Shenandoah.

9. Indianapolis 500. Cutting it a bit close on your list is the largest single day sporting event in the world, the Indy 500. On the last Sunday in March, approximately 400 thousand people gather in Indiana to see who makes it across the finish line first. It's one of the triple crowns of motorsports, and getting to attend one is on a lot of people's lists, even those who aren't racing enthusiasts.

10. Eeyore's Birthday Party. Nowhere near as epic as the other events on this list, but if you're young or young at heart, this festival is great fun. Another Austin, Texas event, this one is on April 25th. Created as a fundraiser to benefit non-profit organizations, this family oriented event has garnered a bit of a reputation by appealing to college students fond of a certain herb. But don't let them put you off, they're likely to just be in full costume playing acoustic guitar on the grass. It's a safe, silly, and fun event that reminds you what childhood should be about. Plus, who wouldn't want to wish grumpy ol' Eeyore the happiest of birthday parties?

The Indy 500 is at the end of May.

Although a few of these events do not take place in the US they are worth noting. It is in the opinion of the reader as to whether they constitute as epic. That being said, some of the events occurring in 2010 begin on 12 March with the Vancouver Paralympic. Daylight Savings Time starts 14 March. Dubai International Arabian Horse Championship is scheduled for 18 March. Hubble 3D is scheduled for release 19 March. The following month brings the Master's Tournament on 5 April. The 6th Global Scavenger Hunt begins 9 April. The Kentucky Derby is 1 May. Other important dates in May are 12 May with the start of the Cannes Film Festival, the Nascar Sprint All-Star Race, and 30 May with the Indianapolis 500.

*references cited below

1) FILM & MUSIC: SXSWeek 2010, March 12-21 in Austin, Texas (South by Southwest SXSW Conferences & Festivals offer the unique convergence of original music, independent films, and emerging technologies. SXSW is the premier destination for discovery.)
http://sxsw.com/

2) PHOTOGRAPHY: FotoFest 2010 Biennial Contemporary U.S. Photography, March 12 - April 25 in Houston, Texas (The FotoFest Biennial is the longest running and most acclaimed photography biennial in the United States.)
http://www.fotofest.org/biennial2010/

3) SPECIAL INTEREST: GovSec and US Law Expo and Conference, March 23-24 in Washington, DC (GovSec and U.S. Law provide the products, strategies, tactics, education and networking for the professionals whose mission is to secure our nation and their communities.)
http://www.govsecinfo.com/Home.aspx

4) SPORTS: 2010 Masters Golf Tournament, April 8-11 in Augusta, GA (The Masters Tournament has been going on for well over six decades and is widely considered to be the premier golf tournament in the United States.)
http://www.coasttocoasttickets.com/golf/masters_tickets.shtm

5) BROADCASTING MEDIA: NAB Association of Broadcasters Show, April 10-15 in Las Vegas, NV (NAB is the world’s largest digital media industry event attended by leading media, entertainment and communications professionals.)
http://www.nabshow.com/2010/index.asp

6) AUTO RACING: Toyota Grand Prix of Long Beach, April 16-18 in Long Beach, CA. (America's #1 Street Race. Features the IndyCar Series, battling wheel-to-wheel on the famed 1.97-mile, 11-turn seaside street circuit.)
http://www.gplb.com/

7) ENVIRONMENT: 40th Anniversary of Earth Day April 22 in Washington, DC (The flagship event will be held on the National Mall in Washington, DC)
http://www.earthday.net/earthday2010/

8) MUSIC: New Orleans Jazz and Heritage Festival, April 23-24 and April 30-May 2 in New Orleans, LA (Best-known Jazz music festival in the US.)
http://www.satchmo.com/nolavl/jazzfest.html

9) MUSIC & FOOD: Gulf Coast Zydeco Music and Crawfish Festival, May 14–16 in Daphne, AL (Some of the best Zydeco dance bands that lower Louisiana has to offer. Great array of food featuring crawfish and other Creole and Cajun dishes from Louisiana.)
http://www.gulfcoastzydecomusicfestival.com/

10) PERFORMING ARTS: San Francisco International Art Festival, May 19-30 in San Francisco, CA (Performing arts groups from ten countries convene in San Francisco for the Seventh Annual San Francisco International Arts Festival.)
http://www.sfiaf.org/