(if you've heard the riddle & know the answer please don't spoil the fun) 2 dads and 2 sons walk into a pet shop, they buy 3 dogs. There is a dog for everyone, how is this possible?
2 dads = One grandfather (Father of one), The father (Father of one and son of one) 2 sons = The Father (Son of grandfather) and the son (Son of the father)