Quake Live is a free to play 3D multiplayer online FPS created by the legendary studio id Software. Mostly similar to Quake 3 Arena, this is a game that is played via a simple web browser. The browser plugins are optimized in a way that even computers with lower specifications are able to run it at impressive speeds, something that is part of the Quake legacy.
Warface is a free to play 3D military MMOFPS developed by Crytek (best known for developing Far Cry, Crysis and CryENGINE) with next gen visuals, AI and physics powered by CryENGINE3, the same game engine behind Crysis 2.
Based on the popular Narutoanimeseries, Unlimited Ninja (Ultimate Naruto) is a turn based fantasy browser RPG that pits teams of Ninjas against the forces of the Nine-tailed Demon Fox, using an assortment of abilities and various equipment to lay their claim to triumph.