SwitchBoard is a prototype meta-programming environment. It is meant as a proof-of-concept of novel ways of thinking about software creation, as informed by the philosophy of Disability-Driven Development.

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

Technitium DNS Server is an open source authoritative as well as recursive DNS server that can be used for self hosting a DNS server for privacy & security. It works out-of-the-box with no or minimal configuration and provides a user friendly web console accessible using any modern web browser. Implements not only ad- and malware blocking but DNS-over-TLS and DNS-over-HTTPS. Authoritative server as well as recursive resolver. Implements HTTP and SOCKS5 proxy support for tunneling resolution requests through Tor as well as proxy servers.

Written in Csharp. :(