Has anyone else tried these DVDs??? Just got them in the mail...holy crap! my butt is KILLING me today!!! seriously, i have one sore hinder. they are only 20-35 minutes long, but it is a SERIOUS cardio non-stop workout. no rest between exercises (at least no stopping...they slow the pace down a tad). i admit, i had to stop from time to time to catch my breath...and i sweated like CRAZY. granted, i'm pretty out of shape, but still, you really feel those squats and lunges. i'm using butt muscles i didn't even know existed...and i have to admit, i'm curious to see how well it works. that alone makes me want to stick with it. i think these may actually be worth the $60.