Three times - Once when you tell it, once when you explain it, and once when she gets it.
Just one provided there's a programmer around to explain how to do it.
Sure, you know how it works, but now it's dead.
So that you can tell them apart from feminists
She'll tell you
Stall
Criminal: You said it was time to spill the beans.
No eye-deer. EDIT: I totally messed this joke up. Please give me another chance with another joke
The punchlines are too long.
Tell her a joke on a Monday!
Tell her a joke at Christmas