What are some jokes that only Americans can easily understand?

George W. Bush was frustrated by the jokes that satirized his intelligence. His old friend, Vice President Cheney assured him: Those are just stupid jokes, and there are many stupid people out there. I can prove it to you. Cheney took George W. Bush to the streets. Yang took a taxi, told the driver the address and said, I'm going home to see if I'm at home. The taxi driver dragged George W. Bush and Cheney to that place without saying a word. After paying the money, Cheney said to George W. Bush: Look how stupid this driver is! George W. Bush said: Yes, there is a public phone where we get on the bus. All he has to do is make a phone call!