I'm definitely a DDR fanatic. I have three PS2 games that are DDR, and one that isn't. Plus I bought a Cobalt Flux metal arcade pad. It was pricey -- over $300 with shipping -- but cheaper than a year-long gym membership. And I've gotten more use out of it than any gym membership.
I'm still not all that great. I can do any song at the second level, quite a few at the third level, a handful at the fourth level (heavy, I think?) and only one or two at the fifth and final level. But it's fun. I've got some songs that aren't as challenging stepwise but have a lot of jumping around to get my heartbeat up that I like to do. I even have a few self-designed courses that I refer to as foods (i.e., "this is the course I play if I want a cookie, this is the one I play if I want some potato chips...") and play through one of them if I feel like having a treat.
The only thing is that I'm a big woman, and a busty woman, and even with a sports bra, er, there's a whole lot of shakin' going on. :P So I'll only play with other females, or in front of my cats, with the blinds closed.