Check out this game I found quite a while back:

www.stepmania.com

info about stepmania see:

www.en.wikipedia.org/wiki/StepMania

its pretty kewl - just download the program - then look for some songs to dance to, like here:

http://www.flashflashrevolution.com/sims/

its good for those odd summer rainy days (which to be coming around alot more often than usual)

have fun!