Let's get to the limitations right away: Mac and even Firefox users will have to sit this one out, since it only runs on a PC, in Internet Explorer. And XP is probably your best bet, too, since Vista users have apparently reported some glitches when using the beta version of this very cool new interactive tool.

All that aside, though, the Visible Body, a new, and free, interactive experience from Argosy Publishing, is pretty mind-blowing. It's Gray's Anatomy in 3-D. (The book, people, not the show.)