Since it is cold as balls outside, maybe everyone could throw up a workout that you do when you cant get out and run. When I am at work, 3 of us do a different workout every shift day. one of them is a 300 workout. (not to get the airbrushed abs like in the movie). 300 total movements. I think it is on you tube, and includes a lot of lower body stuff like lunges and squats. these really get your heart rate up, work the crap out of your core, and use minimal weight. Trust me, you will be sore. This is my workout 25 pushups 25 sit ups 10 step ups per leg with 25# dumbells 20 bike kicks 10 Cleans (long bar with 25#'s each end, start in squat position and throw to chest) if you still don't get it, check www.crossfit.com videos 10 standing side crunches per side. I hold a 45# plate in the opposite hand 20 leg raises 20 bench dips plank 60 seconds each side plank 60 seconds rest and repeat 2 more times try to transition from one to the next with minimal rest between. Take five minutes at the end of the rotation and get a drink, let your heart slow down. this can be done in 30 minutes or less.