WiFi Signal - Monitor and troubleshoot your Wi-Fi connection
FlexSim - Simulation software to model, simulate, predict, and visualize systems in manufacturing, material handling, healthcare, warehousing, mining, etc.
BARS - Easily create and share raps
ns-3 - a discrete-event network simulator for internet systems
Rapchat - Create, share, and discover freestyle raps
Paessler Multi Server Simulator - Paessler Multi Server Simulator is inexpensive and robust software that helps you power massive-scale testing.