Paint samples, playing cards, sponges, sugar packets, matches...

Original Purpose: Taking up space in your kitchen and desk drawers.
Aha! Use: It's all there, and now you know why you've never gotten around to throwing it out: a private, inexhaustible stock of Valentine-card-making props. Dead AAA batteries ("I get a charge out of you"), old lollipops ("I'm a sucker for you"), stray keys ("the key to my heart"). Sit yourself down and grab a pile of craft supplies — construction paper, scissors, markers, tape, X-Acto blade, large-eyed needle and strong thread (or dental floss!), doilies, ribbon saved from the last party. Don't worry about getting the edges straight. It's the message that counts.
Reward: Recycling with heart.