Here's one for ya:
Why is a man like a snowstorm?
Because you don't know when he's coming, how many inches you'll get, or how long it'll stay.
And one more for good measure:
A man was going door-to-door doing a sexual survey in Jeff's neighborhood.
"How often a week do you have sex with your wife?" asked the inquirer.
"Three times," Jeff said without hesitation.
"That is once more often than your neighbor," the inquirer said, writing.
"That makes sense," Jeff said, "after all, she's my wife."