StepMania is an Open Source Dance Dance Revolution for your Windows PC. Indeed, it seeks to be a platform for a multitude of rhythm game clones. The project appears large and well-established, with sexy screenshots, a 3.0 version number, and various fan forums and web sites. You can play StepMania with a Playstation dance pad and a "Boom"-brand PS->USB adaptor (other PS->USB adaptors are not recommended, according to the Readme). Install your own songs, develop your own dance patterns, create your own skins and more. See also the StepMania SourceForge page.