Making valentine cards is very fun filled activity when done in a group. You can do this craft activity in a group. Invite your friends and their kids, and give coloring pencils, craft papers, craft scissors, glues, buttons, beads etc to the kids and ask them to make lovely valentine cards. Moms can help their children in the process.
Those who are young and cannot make a card on their own can be engaged in valentine card coloring. You can give them valentine color sheets and ask them to color the sheets with crayons and other colors available.