Two tourist groups, one made up of all blondes and one of all brunettes, charter a double-decker bus for a weekend in Las Vegas. The brunettes ride in the bottom of the bus and the blondes ride on the top level. The brunettes down below whoop it up and have a great time when one of them realizes she doesn't hear anything from the blondes upstairs.
She decides to go up and investigate. When the brunette reaches the top, she finds all the blondes frozen in fear, staring straight ahead at the road and clutching the seats in front of them.
The brunette says, "What is going on up here? We're having a great time downstairs!"
One of the blondes says, "Yeah, but you've got a driver!"
