Open the door, Shut the door

No no, you're not being rude - you're working your rhomboid! (That's part of your back)

Muscles worked: Rhomboid (see http://www.rad.washington.edu/atlas/rhomboids.html)
Time to complete: 5-6 minutes
You will need: Dumbbells (about 5-10 lbs)

1. Stand straight up, feet close together but not touching, arms extended and straight against the body.
2. With dumbbells in hand, bend your elbows into a 90 degree angle.
3. While keeping the upper part of your arm (shoulder to elbow) close to the body, slowly pull the dumbbells (and the bottom half of your arm) away from each other, ending about 45 degrees from where you started - this is the "open the door" movement.
4. Now, bring the dumbbells back to where you started, right in front of the body (over the toes) - this is the "close the door" movement.
5. Repeat for a total of 12 repetitions, put the weights down and rest 30 seconds, then repeat 2 more full sets.