In todays flashy market, open source games are generally overlooked for more flashy (Explosion Oriented) games. Open source games however, deserve some recognition (Hell, they're FREE!) This is what this topic is for. I would like to know about everyone's favorite open source games, programs, and whatever else fits (as long as it's free - and appropriate).
"We can categorically state that we have not released man-eating badgers into the area."

-UK military spokesman Major Mike Shearer