> A blonde woman goes into a bank

etc

Marvellous. Here's my favourite one, although it's a standard *dumb* blonde joke.

A blonde gets tired of all the jokes about blondes and decides to dye her hair brown. To her surprise, as soon as she does this, she becomes really clever. One day she is out driving in the country and has to stop for a farmer herding sheep across the road. [*This happens a lot on New Zealand rural roads. I don't know if there's a U.S. translation of this joke.]

She thinks they would make cute pets, and decides to use her new brainpower to get one. She calls out to the farmer, "If I can count how many sheep in this flock in five seconds, will you give one to me?" He is surprised, but agrees.

The woman looks rapidly at the flock and announces "There are 153." The farmer is amazed. "You're right! Go on, take your pick." She chooses one and puts it in her car.

The farmer says, "OK, now I've got a question for you. If I can guess your real hair colour, will you give me my dog back?"