If you haven't played Rage or Rage HD, now's the time. It'll be free on iTunes for the next week.
Why the sudden burst of charity on the part of id Software? It seems that a promise was made that they would be free for a week if their Facebook page got 100,000 "Likes." Needless to say, that goal has been reached.
For the uninitiated, Rage and Rage HD are rail shooters, and darn pretty ones at that. You can download them here.
The full game will be out October 4.