At my elementary school, the rule was that either you made valentines for every person in the class or you didn't get any at all. I was pretty much the only person who gave out homemade valentines and thought up what I put on them.
In high school, they let you buy and send cards with "candygram" (a disgusting cherry-flavored heart-shaped lollipop) to people. I always sent them to my friends. No one ever really sent me one though.
