For a while I was really interested in getting a metal Pump it Up pad, and adding the PC version of Pump it Up to my cabinet. But then I realized that 80 percent of the fun in that game comes from the fact that there is usually a crowd watching when I play (not that I am the best at it, but I am good enough to draw a crowd on friday night).
It wouldn't be the same in my room by myself.
It looks like pretty decent exercise, actually - my co-workers are trying to get me to come to pilates class...but that's not gonna happen anytime soon. Besides, think of the mad dance skillz you'd have after playing for a few months?
Now all I need are some MC Hammer pants.... 
First off, Frost, you don't learn dance skills from ddr

just rythm skills and simon says skills.
Paige, stepmania is a ddr simulator, but it also does several other machines like pump it up.
Pretty much everything you will ever need is either at
www.stepmania.com, ww.ddrmaniax.net, or links off of those two sites.