Wife: You’re an hour late getting home from work again!
Husband: I had to work late.
Wife: I can see blue chalk on your fingers; are you sure you didn’t stop by and play billiards with the guys before you came home?
Husband: (pause) err ah.. I’m using blue chalk at work to mark our outgoing shipments and white chalk to mark the received shipments. I’ve found this method to be quite efficient.

The next night he comes home on time and sits down to dinner.

Husband: We’ve been married ten years and you’ve never made TV dinners. You know I don’t like TV dinners.
Wife: It’s not a TV dinner!
Husband: Then why is it in a TV type severing tray and not on a plate.
Wife: (zero hesitation) I buy the tins and cook your entire dinner at once. I’ve found this method to be quite efficient.