CoffeeMud is a text-based virtual reality game engine (a MUD). It is a mature, full-featured Java codebase. It includes web (HTTP) and email (SMTP) servers, chat (IMC2 and I3) and web clients, and supports ANSI, MXP, and MSP.
An open source VR headset with SteamVR supports for $200
...We designed an affordable motherboard that runs the Relativty Firmware, it is based on the Atmel SAM3X8E ARM Cortex-M3 processor and uses an MPU-6050 as it’s IMU. The naked PCB and the components to solder on, cost in total about 25 dollars.