Zed shares the versatility of the humble cookie cutter:
Nothing is a better investment for Valentine's Day than heart-shaped cookie cutters in various sizes. Aside from the many craft possibilities, they instantly make boring food seem like Fancy Valentine's Food, simply by cutting it into heart shapes. The classic is pancakes on the morning of Valentine's Day, but they also work great on Rice Krispy treats for the class party, toast, sandwiches, cheese, crisp lettuce, mashed potatoes, lasagna noodles, etc.
Heart-shaped mashed potatoes. Now there's a thought.
I saw a cute idea in FamilyFun magazine — use a heart-shaped cookie cutter to make red Playdoh hearts, place one each in cellophane party bags, and hand that out to classmates instead of candy. (Tons of great Valentines ideas on the FamilyFun website, by the way.)