Registration is open for Halo: Reach players to participate in the two-day FLAG (Fight Like A Girl) tournament. Registration costs $10 per person, or $20 per four-player team, and the event takes place from Saturday, October 23rd to Sunday, October 24th. Co-op gamers are not left out - Firefight is featured as one of the four accepted modes.
This will be the fifth annual FLAG tourney. All proceeds benefit breast cancer research and awareness. Since you get to enjoy free DLC for Red Dead Redemption (see here) and Left 4 Dead 2 (see here), you can put your pocket money in a charitable cause. Check out the official site for more details.
Thanks for Wildcard Zen for the tip!
Source: Gamepolitics.com