This is a heads up to all gamers!, Gamestop has begun their 50% Trade Bonus offer. Gamestop site says that the offer begins Today June 4th and ends on June 13th.
So that gives you about a week to go there every single day with bags of games :). Make sure they are games that still got some good value, so you can really take full advantage of this offer.
If you want to know the trade in values of your games, you can check the latest list at Cheapassgamer.