Man, beer, bar

A man walks into a bar and orders a beer. He takes his first sip and
sets it down. While he is looking around the bar, a monkey swings down
and steals the pint of beer from him before he is able to stop the
monkey.

The man asks the barman who owns the monkey. The barman replies the
piano player. The man walks over to the piano player and says "Do you
know your monkey stole my beer." The pianist replies "No, but if you hum
it, I'll play it."