Here are some sites where you can enter codes which give you points to use on prizes ranging from contest entries to tvs! Some of them (like Recyclebank) may not even require you to enter codes, but just do things around the site to earn points! I’ve written the expiration date next to the site name, so you know how long you have before they stop. Have fun!
Biore Prove It! (expires Dec. 31 2013)
Disney Movie Rewards (expiration date not yet announced)
My Coke Rewards (expires Dec. 31 2011)
Pampers Gifts to Grow (expires Dec. 31 2013)
RecycleBank (no expiration date found)