Last year I "heart attacked" my boys' bedroom door so that they awoke on Valentine's Day to this:
My boys loved it so much that we kept it up for the rest of the month. I plan on making it a tradition. It's a good thing that I planned ahead because it took a while to cut all those little hearts--I covered them all in contact paper so that I can reuse them year after year. It will save time--not to mention the cost of all that scrapbook paper--not having to cut out hearts every year.