Looks like the patent for Dance Dance Revolution expires this year:
https://patents.google.com/patent/US6227968B1/en
@NovaSquirrel seriously? 
good things happen when patents get the hell out of the way 
@Chel When they're used as intended I don't mind them very much since the term is actually short enough that things that were important in your life are very likely to be free to use later in your life.
MP3s are a pretty good example, very important, widely used technology that's now usable by everyone for free.
