I'm pretty sure everyone's heard this one...

[vampiress_kat]

Two men meet, let's call them Bob and Joe, meet. Bob invites Joe to a party he is hosting. Now, Bob is a riddle fiend. At the party, he announces to the guests that he has a riddle for them, and that whoever guesses it right gets... I don't know, cookies. Bob points at Joe and says, "Brothers and sisters have I none, but this man's father is my father's son."

Can you answer Bob's riddle?

[spirited_soul]

Bob is Joe's uncle!

[qsxd1]

Bob is Joes father!

[Predaxus]

Bob is Joes cousin!

[whisperknife]

Bob's son

[sudoku]

artificial insemination.... Joe's dad got active sperm!!!