I always do the dc's classroom parties and we always do icecream sundae bars on Vday (cookie frosting on Xmas- I go with what works!). The kids love it! Like a pp said, we do 4 rotating stations- snack, crafts and games. Sometimes I do two games, sometimes I do two crafts. Depends what ideas I have! For first gr., you can totally do Valentines for mom/dad/etc. for the craft. An easy game is to cut out a bunch of hearts, then cut them into puzzle-like halves. Hand them out and the kids have to find the other half and say something nice. This is fun as a whole class activity.