Google's answer to Second Life is a browser-based beta of a virtual world engine called Lively. It's free, requires Windows XP or Vista with IE or Firefox, and takes several install steps to activate and get running. There isn't actually much to do yet, except customize avatars and rooms, stream pictures and video, and chat with friends and strangers. But it's from Google and probably worth a look, if you're into that sort of thing. I seem to remember something very similar crashing and burning back in 1996, but it was probably just ahead of its time - and lacked the backdrop of streaming music and video...
