Check Under the Lid

A passer-by is walking down the street and sees a man jumping up and down on a manhole cover yelling "86, 86, 86."

The passer-by asks the man, "Excuse me, but why are you jumping up and down on this manhole cover and yelling '86, 86, 86'?"

The man says, "Well, I can't tell you that, but if you really want to know, I can let you go under there and find out.

The passer-by thinks for a moment, then his curiosity gets the better of him, and he says, "Okay."

The man lifts the manhole cover, the passer-by steps into the manhole, and the man puts the manhole cover back and starts jumping up and down on it yelling "87, 87, 87"...