1. Have a date. 2. Try not to forget it.
Hose A and hose B (read it out loud)
Because they cantaloupe. (The wife thought of this one... hopefully nobody else has posted it)
They're always trying to 1-Up you.
Boo bae! (Read aloud please)
Someone told him it was 2's day.
When you don't use a condom.
You can actually get through the minefield alive.
He forgot.
Carbon dating.
Carbon-14 is the most common method, I believe.