Not-so-toned abs can be hidden with a one-piece bathing suit or a strategic top, but your arms are always on display. Pick up some light dumbbells (soup cans work in a bind), and do these exercises in a set. 15 reps of each exercise, 3 sets, taking a break between each set. In a few weeks you can start selling tickets to the gun show! (I'll see myself out)
Side Arm Rows
Let arms drop to your sides, a weight in each hand. Now, with your back straight, pull your arms up, elbows bending back, lower, and repeat.
Front Arm Rows
Back straight, arms in front, bend your elbows to the side, squeezing shoulder blades together, pulling the weights up to your chest. Hold shoulder blades together for a moment, and then lower arms back down to repeat.
Dumbbell in each hand, elbows bent at 90 degrees, arms up. With your back straight, lift the weights up, straightening your arms over your head, in a slow and controlled motion. Return to the starting position and repeat.
Overhead Triceps Extension
Exercising each arm independently, start with the dumbbell behind your head, careful to keep it lined up with your spine. Your elbow is bent, and slowly move to straighten it, lifting the dumbbell in a straight line upwards, pausing right above your head before lowering again.