Lumix Engine - Open source 3D game designer and engine written in C++.
Digit - SMS bot that monitors your bank account & saves you money
Grit Game Engine - The Grit Game Engine is an MIT-Licensed Open Source Game Engine that is highly scriptable via Lua.
Olivia - Your new best friend built with an artificial neural network
MOS - Lightweight game engine.
Spendee - See where your money goes