RiVeR stands for «Ruby Virtual Reality». RiVeR is, essentially, a collection of VR multiuser experiments; that you can borrow to speed up the development of you own projects. It’s goal is to leap the gap from single to multiplayer user experience. To grant functionality, it lays on Sinatra and ActiveRecord.
It includes two different but cooperative concepts: a holodeck, which means a VR scene to which other users can send arbitrary code snippets; and the agora, which was meant to host concurrent players in the same scene.
The only thing is that… it’s unfinished. Nevertheless, here you have what I got, licensed under GPL3.