A minimalistic digital logic simulator
FlightGear Flight Simulator: free open-source multiplatform flight sim
Physically accurate and validated GPU ray-tracer
Circuit simulator for power electronics
A distributed flight sim and front end for JSBSim
A simulator for biological and physiological models
Advanced vehicle simulator
RetroPC-SIM is an Arduino project to help to understand how pc works
Ein Simulator für Registermaschinen
Ein Simulator für Turingmaschinen
An accurate, scalable, and energy-aware simulator for WSNs
BlueSky Open Air Traffic sim, (Windows/Linux/Mac, Python 2.x based)
action/combat flight sim
realistic truck simulator with 3D graphics done from zero