I can't think of any off the top of my head, but this bit by Peter Kay always has me in tears.

Also, the technical term is 'Mondegreen'

Edit: I'm also reminded of a Colin Hay one man show I went to years ago where he told a story about a bloke that requested the 'song about the goats' at a gig. Turns out it was Overkill - "Goats appear and fade away". He then went on to tell a long story about a sharehouse he lived in in his youth that decided to get a goat to keep the lawn down. Man that was a good show.