Click to Play this game. It's not great but it is in 3D and it's a Macromedia Shockwave game. As of version 8.5 they have 3D support now.
Up until now there's been no *mainstream* package to make 3D games in. Either you had to be a *real programmer* and use a 3D engine or roll your own or you had to stick with making new levels for Quake. Now you can get the lastest version of Shockwave Studio and whip out games left and right.
Of course I don't expect to see a Jax and Daxter clone anytime soon but it might not be too long before your average first generation Playstation game is tomorrow's throw−away Shockwave game trying to bring traffic to a site. Check out this preview. Or this tech demo. href="http://www.macromedia.com/software/shockwaveplayer/3d_content/samples/letterland/letterland.html">This example was at least mildly interesting. Or how about 3D-Constructor on this page that's loosely based on Sodaplay
And of course as it's Shockwave nearly everybody will have this software installed. Although I wonder, as they are using Intel's tech does that mean it will never run on a Mac or does it work there too? I didn't check