A piece-of-cake Valentine project: bend regular paper clips into little heart shapes. These are jumbo clips I got in a multi-color pack at Target for about $1.50, I think. I fished out the pink ones for this.
You could use them to leave love notes around. Or mark pages you like in magazines. Or hold tiny treat bags of candy shut. Or send a subtle message to the boss you have a crush on. Endless possibilities, really.