Clone Hero - Clone Hero is a free rhythm game, which can be played with any 5 or 6 button guitar controller...
Audacity - Audacity is a free and open-source audio production software suite that includes a surprising array of editing tools and recording systems.
Osu - Osu is Music, Rhythm, Single and Multiplayer video game developed by Dean Herbert.
Oceanaudio - Ocenaudio is a cross-platform, easy to use, fast and functional audio editor.
StepMania - Rhythm game for Windows, Mac, and Linux.
GoldWave - GoldWave. Digital Audio Editing Software. Record • Restore • Convert • Analyze. Fully loaded to do everything from the simplest recording and editing to the most sophisticated audio processing, restoration, enhancements, analysis, and conversions.