This is a combination exercise that works the chest, shoulder and arms. It can also give you a good assisted stretch.
Muscle group: Chest
Lie on a flat bench and grasp a barbell using a medium grip (about 15 apart).
Place the barbell on your upper thighs and lock your arms straight.
Draw your abs in and keeping your back flat on the bench, raise your arms up and in an arc over behind your head (as if you were performing a reverse pullover).
Slowly return the barbell to the starting position on your thighs.