This is one of my favorite drills because it is so tough to "win" :)
Setup: 6' target on a slope (The Target Circle and Target Hole are perfect).
Hit a chip with each iron in your bag - just one ball per club.
Give yourself a point for each ball in the circle, or (my favorite) give yourself a birdie for each 2 in a row in the circle, and a bogie for each 2 in a row out of the circle. (If you shoot even par, you are the Man!)
When you get good at this drill, you have learned to focus and execute a good motion because every swing is totally different.
Let me know when you master this ... I won't hold my breath :)