Here is a fantastic way to incorporate a geometry lesson with Valentine's Day!
Print a copy of the template on red card for each of your students. Cut the heart up and place the pieces in an envelope and give to students to try and piece back together. When they succeed, they'll see a Happy Valentine's Day message from you!
Alternatively, print on white card and give to students to color, decorate, and cut out the heart. They can then give these to friends or family members for a Valentine's Day card.