As a brief RPS article notes, Gaikai seems to be aimed mainly at developers for now. But there are a few games available to play, including Mass Effect 2, Dead Space 2, and The Sims 3.
There’s a bit more info here. Among other things, the articles notes that “At GDC this week, a demonstration of Mass Effect 2 running inside Facebook will be shown.”
The future of gaming? Or at least one future path?