Papervision is a really neat technology that produces 2.5D images on screen in HTML5 web browsers that allows for scripted animation and interaction. It is somewhat open ended and a bit difficult for beginners to figure out. Results are stunning though. For those who prefer a more familiar 3D interface, I recommend CopperCube 3 (free version is is not crippleware) and SimLab 3D (about $120 after 30 days if I recall) for people that want to output their figures on the web (even as games) using either HTML5/WebGL (Chrome & FireFox browse native), Adobe Flash 11 Stag 3 (Browsers/Air, Flash required), or 3D PDF (electronic document,web page with Acrobat plugin).
My signature includes a link to FarmPeeps.com which has a coppercube demo, tutorial and samlpe source file to mess with. Using CopperCube you can make a (simple) 3D game in a night. On the GoldPeeps.com site, I have an example of a a SimLab animated 3D PDF where you virtually explore as a gold prospector works his sluice box in a stream.
EDIIT: CopperCube 3D Tutorial and sample game source here http://www.farmpeeps.com/webgl3d_1.html