StepMania

StepMania is a free and open source, cross-platform rhythm game. It supports common key-based rhythm game formats (including 4-panel and 5-panel dance games among others), as well as keyboard and dance pad controllers. It is customizable with user-made add-ons such as themes, and provides an integrated editor for creating your own simfiles.

StepMania can also be used with dance game cabinets, and has been used as the basis for several major commercial products including Pump it Up Infinity and StepManiaX.