Clone Hero - Clone Hero is a free rhythm game, which can be played with any 5 or 6 button guitar controller...
Machinarium - Machinarium is independent puzzle / adventure game by Amanita Design
Osu - Osu is Music, Rhythm, Single and Multiplayer video game developed by Dean Herbert.
Seekers Notes - Seekers Notes is a Hidden Object, Puzzle, and Single-player Point-and-Click video game with adventure elements developed and published by MyTona.
StepMania - Rhythm game for Windows, Mac, and Linux.
timetrap - Simple command line timetracker.