Did you know that the you can “tweet on Twitter” through your XBOX360? There's a contest right now where they're giving away XBOX360 video games every week this month (September), plus a grand prize of an XBOX360 Entertainment console. All you have to do is follow twitter.com/Upgrade2XBOX360 to be entered to win.
Tell your friends to follow and that counts as more entries. You can also send them direct messages!