I don't know about in the U.S. but in most Canadian EB game stores you can trade in games from the
Wii, PS3, 360 & Possibly
DS/PSP that are a value of $8 or more for one new release. IF you are smart you can ask them over the phone which games you own are worth more then $8 and then bring them to trade in. Dunno about you guys, but getting Far Cry 2 and Call of Duty 5 for a combined $48 ($12 less then the usual price) was a pretty good deal to me.