Here's an easy way to make a cute little envelope out of a heart for Valentine's Day.
Start with a heart. Score the heart in thirds both horizontally and vertically.
The center square is the size of your note. Crease your score lines, folding in each side. Then fold the top of the heart down, insert your love note and slide the point of the heart into the slit.
Add embellishments if desired and slip one (or two) into a lunch bag or a briefcase, hide them in a drawer, leave one on the dashboard, prop one on someone's keyboard. Enjoy!