[Rob M]

A little boy and his father went into the Chemist.

The boy spots the condom display behind the counter and starts asking his Father questions:

Boy: "Dad, why do those ones come in packs of three?"
Father: "Well son, those are for School Boys. One for Friday night, one for Saturday night, and one for Sunday night."
Boy: "So why do those ones come in packs of six then?"
Father: "The ones that come in packs of six are for college boys. Two for Friday night, two for Saturday night, and two for Sunday night."
Boy: "Oh.....so what about those ones then? Why do they come in packs of twelve?"

At this the Father turns to his son, and with a tear in his eye he says: "Son, those ones are for married men. One for January, One for February.........."