10 Lbs of Mushrooms is a bit more than you might enjoy at one time. I'd think about drying or freezing them. Here's a pretty good article:
http://polishpoland.com/preserving_wild_mushrooms.htm

Crimini mushrooms are really great as the shell of a stuffed appetizer. Stuff them with your favorite risotto and you'll have a gluten free treat. Since you have a bunch of the little fellas, I'd deliver some of these appetizers to friends and neighbors just before dinner time to be friendly.

Some recipes to consider:

Yeast Free, Gluten Free Portobello Sandwich
http://cook-aunaturel.blogspot.com/2009/03/yeast-free-gluten-free-portobello.html

Portobello Spring Green Salad with Buttermilk Dressing Recipe
http://www.bookofyum.com/blog/gluten-free-menu-portobello-spring-green-salad-with-buttermilk-dressing-recipe-3535.html

Quinoa Stuffed Portobello Mushrooms
http://www.bookofyum.com/blog/gluten-free-menu-portobello-spring-green-salad-with-buttermilk-dressing-recipe-3535.html

Grilled Marinated Portobello Mushroom Salad with Creamy Herb Dressing - Gluten Free
http://glutenfreetasteofhome.blogspot.com/2009/06/grilled-marinated-portobello-mushroom.html

Portobello Relleno
http://www.grouprecipes.com/25130/portobello-relleno.html

10 lbs is way more than you can eat at a time unless you are having a big party. What I would do is enjoy a yummy recipe with some of them & then dry the remainder. Dried mushrooms last nearly forever (a year or more!) & can be easily reconstituted when you need them. Reconstitute in red wine for pasta sauce, or sherry for soups or in water if you're alcohol-free. Save the water you use & make stock with it. The possibilities are endless.

Here are the recipes...

For the fresh ones:

Stuffed Crimini Mushrooms with Gruyere Cheese

36 crimini mushrooms, stems removed
½ cup olive oil
2½ cups chopped yellow onion
⅓ cup minced shallot
6 cloves garlic, minced
¾ cup chopped fresh chives
3 fluid ounces lemon juice
2 cups gluten-free bread crumbs or brown rice bread crumbs
5 ouches shredded Gruyere cheese

1. Bring a large pot of water to boil. Add mushrooms, and cook for about 3 minutes. Drain, and set aside to cool.

2. Heat olive oil in large skilled over medium heat. Add the onion, shallot, garlic and chives. Cover and let the vegetables sweat for a few minutes to release the aromas. Remove from heat, and stir in the breadcrumbs and lemon juice.

3. Preheat the broiler. Scoop out the mushroom caps and fill with the bread crumb mixture. Place on a baking sheet. Top with shredded Gruyere cheese.

4. Broil for 3 to 5 minutes, until cheese is melted. Serve hot.

Then dry the rest:

Preheat oven to 150 degrees

Slice cleaned, dry mushrooms with an egg slicer and place into shallow UNOILED pans and let cook for one hour. Turn the slices over by placing an empty unoiled pan on top of the first one & flip the contents into the new pan & place new pan into the oven, cooking another hour, repeating until they dry out.

This is an easy make ahead side dish. Make quinoa in the rice cooker to save effort and time. Add tidbits of your favorite veggies or seasonings. My version is vegan, but if you enjoy cheese, add crumbles of goat cheese or sheep feta to the mix.

You'll need:

1 large Portobello mushroom per person
Olive oil
Balsamic vinegar
Sea salt and ground pepper, to taste

For the stuffing:

Chopped fresh garlic, to taste
About 1/3 to 1/2 cup of cooked quinoa per mushroom cap
A handful of yellow and red grape or cherry tomatoes, halved or quartered depending upon size
1 scallion (spring onion) per person, sliced
A sprinkle of raisins
A sprinkle of toasted pine nuts
Sea salt and ground pepper, to taste
Fresh chopped parsley, basil or mint

Preheat the oven to 350 degrees F. Lightly oil the bottom of a baking or gratin dish.

Gently clean off the mushroom caps; slice off the stems and using a sharp teaspoon carefully scrape out the gills. Place the caps in the baking dish. Drizzle with a scant amount of olive oil and a touch of balsamic vinegar. Season with a little sea salt and pepper. Pre-bake the mushrooms for about 15 minutes to soften a bit.

In a skillet, heat a little olive oil and toss in the garlic. Stir for a minute. Add in the cooked quinoa, tomatoes, scallions, raisins, pine nuts. Season to taste with sea salt and ground pepper. Stir to combine. Moisten with more olive oil, as needed. Gently heat through, briefly. Remove from heat. Add in the fresh chopped herbs.

Stuff each mushroom cap. Bake in the oven for 15 to 20 minutes, till the mushroom cap is tender. Tent with foil to keep it moist.

You can also assemble these ahead of time, and refrigerate. Bake at 350 degrees F. for 30 mi

Start by sauteeing the mushrooms in butter or olive oil.

From there, you have a lot of options. They can be substituted into any meat dish without much change. Add them to steamed or sauteed vegetables. Or just eat them as a side dish, perhaps cooking in a bit of brandy, wine, or port with some broth to make a sauce.

You can also freeze them; it would be hard to eat 10 pounds of mushrooms. Freeze them in one-pound bags and pull them out any time you need them. They'll keep for a couple of months. They're already cooked and ready to go.

The sauteéd mushroom recipe I included on the How to Cook Mushrooms page works very well with crimini mushrooms.

http://allrecipes.com/Recipes/Fruits-and-Vegetables/Mushrooms/Crimini/Main.aspx

^There are so many Gluten free recipes in this link above me! Just scroll down and you can see them all!^