Ok I don't like this one much - but it's something to slap your male mates about when they tell it to you...

Three blondes are stuck on a dessert island and they can't find a way off to mainland. Miraculously they discover a magic lamp - which contains a genie. He says he will grant them one wish each.
The first one says 'I wish i was more intelligent so I could get off this island' - he turns her into a brunette and she swims to the mainland.
The second one says 'I wish I was more intellegant than you made her so I could get off this island too' - he turns her hair black and she builds a boat and rows to mainland.
The third blonde says she wants to be the most intellegant of them all - so.. wait for it...
he turns her into a man and she uses the bridge!!!!!!!!!!!!'

Oh. My. God!!!

xLx
p.s. and i am blonde! but don't find them that offensive - depending on what they are. Especially as I have a (very blonde) friend who can really act the dumb blonde at times!