I like this joke by Fitst Lady.

http://seattletimes.nwsource.com/html/nationworld/2002259090_bushdinner01.html

Joking is an essential part of American life.  I found there is at least one joke in every speech in the States.  On the other hand, they say there is at least one apology in Japanese speeches.  Japanese speakers think it necessary to express their humble modesty.  We Japanese people are not so good at making witty jokes; ours  sometimes tend to be offensive.  Back in the States I liked to talk with a grocery cashier or a cafe barrister over some jokes.  This kind of things don't happen in Japan unless we are a recognized frequent customer.