It is clunky on my current non dedicated graphics workstation so I cannot vouch for speed. But if it has reasonable performance on better multimedia desktops, I see a great deal of upside to this framework http://virtualworldframework.com/web/catalog.html
I especially like the google earth demo, shuffleboard and physics

http://virtualworldframework.com/web/faq.html
The Virtual World Framework (VWF) is a means to connect robust 3D, immersive, entities with other entities, worlds, content and users via web browsers. It provides the ability for client-server programs to be delivered in a lightweight manner via web browsers, provides synchronization for multiple users to interact with common objects and environments. For example, using the VWF, a developer can take video lesson plans, objects and avatars and successfully insert them into an existing virtual or created landscape (such as EDGE or Open Sim), interacting with the native objects and users via the VWF interface.