Playfire - Playfire is the global community for gamers.
Vizzed.com - Vizzed is an online community with 1000s of free classic retro games.
StreamMyGame - With close proximities to OnLive, StreamMyGame doesn’t work like it, but it allows users to play whether Windows-based games they have on their systems from anywhere in the world on their Windows as well as on Linux system.
Apple Game Center - Game Center brings social gaming to OS X and iOS apps.
Gaikai - Gaikai is a company which provides technology for the streaming of high-end video games.
Tanglet - Tanglet is a single player word finding game based on Boggle.