Here is a new video with Craig Ballantyne showing a very easy way to get in a very fast workout using timed intervals.
I used this as the basis for my quick workout at home. I didn't go to the gym this morning (it's -17 degrees!) but I have no excuses to not work out.
200 Kettlebell swings
30 sec swing, 30 sec marching in place x10
20 sec squatting, 10 sec hold at bottom x8
20 sec push ups, 10 sec hold at top x4
Stability Ball roll out
20 sec roll outs, 10 sec hold extended x4
20 sec jumping, 10 sec rest x5
20 sec burpees, 10 sec rest x5
Took about 25 minutes total time. And got a pretty good workout!