This is a bit nifty. A Russian company called Alternativa are working on a 3D engine that runs in straight, browser Flash. And flipping crikey, it's not bad.
There's a couple of demo areas you can trudge about - a science fiction-themed bunker (with footsteps I'd swear are from Deus Ex, and I know the bleepy noises too - someone please tell me in the comments), and an outdoor ancient ruin in the sunshine. Check them out. Be a bit impressed.
The potential for this is rather huge. If this is what Flash 9 can do, and Alternativa are saying Flash 10 is already dramatically improving performance, just think what Flash 20 will be capable of.
In fact, Alternativa have good ambitions for the project. Future plans include dynamic lighting, bump lighting, paralax mapping, 3D sprites, and animation and physics additions. Their brains being farther reaching than mine, they don't only see the gaming possibilities for this. Think about architects wanting to show their plans without the customer needing to install CAD programmes. (Take a look at this demo for an example of how smooth this is). Or 3D spaces for interactive advertising - how much more likely would you be to play with the banner if you could walk around inside it? Thanks to Mr Parkin for his ever-excellent tippage.