The entry period for the sweepstakes is seven full days, and you can get a new entry for each day you play a Halo 3 multiplayer match online. They've got more than a thousand prizes to give away, and the Grand Prize is a limited-edition, framed piece of Halo 3 artwork (see picture below).
Jolly Green
"Jolly Green" is a Limited Edition Giclee Print on Paper by Acme Archives Limited sure to be prized by any Halo fan. This hand-numbered piece is limited to 150 pieces. This particular piece is custom matted and framed for the Grand Prize Winner of the U.S. Army Heavy Weapons Play & Win. Don't miss your chance to win this rare piece of Halo 3 art that was featured on the instruction manual in the Halo 3 Collector’s Edition.
Just register your gamertag before midnight ET on February 15, and then play in an online multiplayer match between 12:01 A.M. Eastern Time (ET) on February 9 and 11:59 P.M. ET on February 15, 2008 to enter. You'll score a new sweepstakes entry for every day you play during the entry period.
One (1) Grand Prize:
Limited Edition, framed piece of Halo 3 Artwork with commemorative Heavy Weapons plaque and certificate of authenticity
One thousand two hundred fifty (1,250) Daily Prize Winners:
800 Microsoft Points
Read the rules, and how to sign up
here.