Pariah
Outside Influence

Q) Why did the time traveller cross the road?
A) To count the chicken before it hatched.
Q) Why did the time traveller quit smoking?
A) He felt guilty about dropping a cigarette end at a London bakery in 1666!
Q) Why did the time traveller take his ghetto blaster back to the Cretaceous Period?
A) So he could "walk the dinosaur!"
Q) Why did the time-travelling pervert never celebrate Father's Day?
A) Because he was his own father.
Can anyone think of any more? Preferably clever rather than profane.