Astronauts
Why is an astronaut like an American football player?
They both want to make safe touchdowns.
Inferiority
My inferiority complexes aren't as good as yours
Cats
Do radioactive cats have eighteen half-lives?
Astronauts
What does an astronaut do in the morning before he puts on his clothes?
He takes a meteor shower.
Clocks
Did you hear that the man who invented the clock has written his autobiography?
It's about time.
Breath
What always becomes more difficult to catch the faster you run?
Your breath.
Ghosts
What do you call two ghosts who repeatedly press your doorbell?
Dead ringers.
Waiters
Waiter, waiter, this food isn't fit for a pig.'
'Very good, sir. I'll go and get you some that is.'
Lawyers
What did the lawyer name his daughter?
Sue.