Condom Value Packs
A boy goes to the drugstore with his dad and sees the condom display.
Boy: Dad, why do they sell single condoms?
Dad: Those are for high school kids on Friday nights.
Boy: So, why do they make packs of three?
Dad: Those are for the college kids for Friday, Saturday, and Sunday nights.
Boy: Then why do they make packs of 12?
Dad: Those are for married couples - you know, January, February, March...