Virtual Reality Chat (VRC) is developed using a framework (Yaf3D) which combines robust software libraries such as OpenScenegraph, Lua, ReplicaNet, and more. VRC provides text and voice chat in a 3D environment. YAG 2002 project is their home.
...It's working on the new DirectConnect (ADC) network. You can create hubs and bots with extra features. It supports TIGR, SHA1 and UCMD extensions of ADC protocol, and Lua scripts.