Here's a great Primal exercise you can do if you have any Olympic weights. It is great for the hips and quads:
Lay a 45-pound plate on the floor in front of you; you'll need about 20 feet of clear space ahead. Squat, wedge your fingers under the side of the plate closest to you, and drive upward with your legs. When the plate is vertical, guide it forward until it is flat on the ground again, but on its opposite side (don't just let it drop to the floor and bounce).
I do three sets of 24 flips (12 across the room and 12 back). It seems easy at first but your quads will be begging for mercy pretty quickly.
Do this after you've completed your regular strength training workout. I do this twice a week (Monday and Friday).