APC magazine has posted its list of the Top 5 free open source games, along with a list of other free games which come highly recommended. Top of the list is a Super Mario-inspired 2D platform game called Secret Maryo Chronicles. Also on the list are a couple of strategy games, including Free Civ and a first person shooter called Alien Arena. As a bonus they've got a list of 'runners up' and a list of 'free but not open source' games including Sam and Max Episode 4. Should be plenty to chose from if you're looking for a free game to chew up some of your downtime.