The Champions League is a European club soccer tournament that begins in August of every year, and culminates in a final the following May. Other than the World Cup and the European Cup, the Champions League is widely regarded as the most important soccer event in existence. Every major league on the continent sends teams, totaling 32 in all (after a qualifying period). A league's slots in the tourney are awarded based on the strength of said league; for instance, the English Premier League, widely regarded as among the very best in the world, has four slots reserved.

After a qualifying period in which the hopefuls are pared down to the final 32, the teams then compete in a group stage, with the winner's advancing into the knockout stages, starting with the round of 16. The winners in the knockout stage are determined with a home-and-home series, in which one game is player in each team's stadium, and the winner is the team with the largest aggregate goal total. If the two teams tie, the winner is determined by the squad with more goals as the visiting team. If they are tied in both, i.e. if there have been two 1-0 games, then there is an extra-time period and, if necessary, penalty kicks. The final is different; it's only one game, and it is played in a pre-determined site. The winner of the single final takes the all the marbles.

The UEFA Champions League 2010 edition is slated to begin May 22, 2010.

The Champions League (and it's antecedent, the UEFA Cup) has been existence for more than half a century, with the first tournament being won by Real Madrid in 1955.http://www.europeancuphistory.com/euro56.html

Over the years it has gone through a number of different changes altering the tourney's form and organization. Before 1992, the tournament was known as the European Champions Cup, and was open only to the winner of each league in Europe. That year, the name was changed to the Champions League, and in the late 1990s, the competition was opened to non-winners.

The most successful team in the history of the Champions League is Real Madrid, which also won the first five tournaments. The pattern in past years has been parity among the European powers. No team has repeated as champ since 1990, when AC Milan won their second title in a row. From 2000 to 2009, three teams won a pair of titles (Barcelona, Real Madrid, and AC Milan), and the other four titles were distributed to a quartet of one-time winners. http://www.europeancuphistory.com/euro03.html

The 2009 winner of the Champions League was Barcelona, who defeated Manchester United in the final.http://news.bbc.co.uk/sport2/hi/football/europe/8060878.stm Barcelona started the game on the defensive, but a goal by Samuel Eto'o 10 minutes in stabilized the flow of the game in Barcelona's favor. Thanks to a dominating performance by Barcelona midfielders Andrés Iniesta, hailed afterward as the best player in the world by Manchester's Wayne Rooneyhttp://soccernet.espn.go.com/news/story?id=650359&cc=3888, and Xavi, the eventual Man of the Match, the winning team dominated the game after the shaky beginning, and a header from Lionel Messi in the second half, Barcelona pulled away for the 2-0 victory.

Manchester United and Barcelona reached the finals with victories over Arsenal and Chelsea, respectively. Man U advanced with relative ease, scoring a 4-1 overall victory in the two legs, while Barcelona needed a last-minute goal to advance. The top scorer was Barcelona's Messi, who wound up with nine goals.