CSSBattle - Play against others in golf with your CSS skills
Machinarium - Machinarium is independent puzzle / adventure game by Amanita Design
Geektastic - Geektastic is a platform that manages peer reviewed code challenges supported by a community of qualified software engineers.
Unmechanical - Fun and atmospheric side-scrolling puzzle adventure.
DevBattles - Find out which framework reigns supreme
Limbo - “Dark, disturbing, yet eerily beautiful, Limbo is a world that deserves to be explored.” Joystiq. “Limbo is as close to perfect at what it does as a game can get.” Destructoid. Buy LIMBO: Special Edition.