TENNIS ELBOW

A guy's out jogging and he spots a brand new tennis ball lying in the road. He picks it up and slips it into his shorts' pocket. Later, he's standing on a corner waiting for the light to change.

A blonde is standing next to him, and she sees the bulge in his shorts, so she says, "What's that?"

He says, "Tennis ball."

She says, "Oh, that must be painful... I had tennis elbow once."