what is the difference between a duck?
ANSWER: both legs are the same!
Unfortunately, I must admit that I almost understand the joke =-S only because I've heard the (dare I say) "correct" version: Q: What's the difference between a duck? A: One of its feet are both the same. The humour being precisely the fact that it does not make sense ... the listener is supposed to be confused after hearing the question.
whats the difference between a duck. and what excatly??! joke would have been funnier if it made sense...