Try this awesome new elliptical workout! I know you will have fun! The incline will help build your perky butt and the resistance will tone your calves, thighs, quads, and hamstrings - all while torching a ton of cals!
I hate the treadmill but for those who don't: TREADMILL SHREDMILL WORKOUT! It's 45 min long with a 5 min cooldown. This is part of my bikini comp cardio. And yes, you CAN last this long on a treadmill. Trust me.