The more I work, the less mentally demanding games I want to play to cool off. An online match of Street Fighter 4 after a long day of coding does wonders for taking your mind off bugs and backlogs.
Switching platforms also helps. Close the laptop, sit on the couch, turn on the xbox.
Cool! I'm discovering that while there seems to be a high correlation between slackers who don't know how to work and gaming, there also seems to be a high correlation between human machines and modern gaming. I like this!
Team Fortress 2 (PC) is still a big draw for me,even after playing it for a few years. It's easy to drop in and play but also has a lot of variety and team dynamics.
GT5 (PS3) online, though unless playing with friends can be frustrating with wreckless online racers.