"TABATA THIS"
:20 on, :10 off for 8 rounds of each:
Squat
Jerk (55lbs)
Pullup
Situps
The clock keeps running. Don't take more than the standard :10s break between exercises.
This stuff WORKS, folks. Here's the citation for the original research on high-intensity interval training using the Tabata method.
History: the original 'Tabata Machine' was sold in the 1980s in Playboy, Fortune, Forbes, and some others. It was also picked up and sold en masse by Tony Robbins as he toured in the early days.