gonav: Source Engine navigation mesh parser written in Go with pathfinding support
altPUG: Alternate match making and PUG system for Counter-Strike: Global Offensive
Celestial Engine: 2D Deferred Game Engine for Fast Game Prototyping (MonoGame/FarseerPhysics/C#)
in_lay: A fully skinnable media player (C#) - CodePlex
netAudio: A media playback system (for use with in_lay) based on libVLC (C#/Interop) - CodePlex
netDiscographer: A media library system (for use with in_lay; source found in in_lay repo) with a SQLite backend (C#/SQLite)
netGooey: A fully skinnable XAML-based GUI system (for use with in_lay; source found in in_lay repo) (C#/WPF/XAML)
Deferred 3D Rendering Engine (XNA/C#) - Screenshot