High Fidelity

TrackStrap™ compatible and Vive Tracker features: 

"The future for VR will fulfill the promise of completely lifelike communication at any distance," said Philip Rosedale, CEO, High Fidelity. "With the Vive Trackers, the capture of the detail and nuance of body language is now possible for the first time."

From the Steam Page: 

High Fidelity is a free, open source, multi-user virtual reality platform. Experience VR with friends old and new, build anything, and host your own VR space.

Check out the Steam Page