Forgive me if this has already been mentioned. I just found out about it.
If you go to http://assassinscree...ds/rewards.aspx you can earn rewards for credits. Seems to be only digital items left in the rewards. You can get in-game Xbox codes for Assassin's Creed. You get the codes instantly after redeeming them.
Also, it seem that you can keep doing the spin to win game over and over again. Do 5 spins. Then go to the link again at http://assassinscree...-win/index.aspx and it lets you spin 5 more times. Keeps letting me do it.
The rewards are at http://assassinscree...ds/rewards.aspx
Saw someone on SD post this. Supposedly the rewards program ends on May 9th.