OpenSimulator is an open source multi-platform, multi-user 3D application server. It can be used to create a virtual environment (or world) which can be accessed through a variety of clients, on multiple protocols. The optional Hypergrid allow users to visit other OpenSimulator installations across the web from their 'home' installation or grid.

OpenSimulator allows virtual world developers to customize their worlds using the technologies they feel work best - we've designed the framework to be easily extensible. OpenSimulator is written in C#, running both on Windows with the .NET Framework and on Unix-like machines with Mono. The source code is released under a BSD License, a commercially friendly license to embed OpenSimulator in products.

Git repo: git://opensimulator.org/git/opensim

The metaverse is here: an immersive Web full of social virtual and augmented reality experiences. However, mega-corporations want to lock it down and wall it up to make another addictive, toxic ad-selling platform. We’re taking it in a different direction because we dream of a democratized new era of the Web where creators own their content, users own their data, and no single entity exhibits undue influence on the community as a whole.

Immers Space is a social networking application that runs alongside your Immersive Web experience. It provides account registration and login for your site, allows users to login to your site with their existing accounts from other immers, and publishes social updates for users on your site (e.g. sharing a link to invite friends to meet up at your site).

Github: https://github.com/immers-space/

Javascript, but it's supposed to run in a browser. What can you do?

An open source VR headset with SteamVR support for $200us. Steam VR support. Natively displays 2K resolution at 120FPS. Compatible with Arduino. Experimental Body-Tracking. Relativty is not a consumer product. We made Relativty in my bedroom with a soldering iron and a 3D printer and we expect you to do the same: build it yourself.

The history of Iron Man's heads up display.