[rixatrix]

I use a stationary bike at home. Boy, do you feel it in the glutes! My butt is so sore right after I finish...I think the important thing is to work at a resistance/speed that's difficult for YOU, and spike your heart rate. It seems like you could do HIIT with nearly anything - swimming (1 sprint lap, 2 rest), jump rope (30 seconds as fast as possible, 1 minute easy - although I dare you to try it), rollerblading...you get the idea.

I personally use the bike because 1) it's in my own home, so it's convenient, and 2) I have foot problems occasionally that running seems to exacerbate. I get a good workout on the bike. It's always nice to be soaked in sweat after 20 minutes.