There is a YouTube video making the rounds, purporting to show VMWare Fusion running a 3D Accelerated/Direct-X based game in Windows, running under Mac OS X, and doing it fairly smoothly.
Fake or real? Looks real, but considering that VMWare Fusion shares a codebase with the VMWare Workstation (for Windows), it seems like even if it was a Windows-based machine with various changes to make it look like Mac OS X, it still is pretty clearly running under VMWare, which means that at some point it would end up in Mac OS X.
It doesn’t look like it’s a new game, but it’s still impressive.