I'm not sure if this has the koffee_brown Seal of Approval(tm), but I have been doing planks (elbows and toes on the ground, back *flat*, no cheating by rasing your butt in the air). First-timers start at 20 seconds; over the course of a few weeks work up to 1 minute, 2 minutes, 3 minutes . . . 2 or 3 reps. You have to contract your abs to keep the proper posture, and it is tough!
Though I could be wrong, and it could turn out to be some sort of elbow or toe exercise in disguise. Waiting for my review!
