Send a heart attack. (write one thing you love about them on each heart) I love this! This would also be awesome to send with a message for the receiver on only one heart that could be teathered to the lid and instructions to pass it along to someone else
Easy homemade Play Doh. I love the idea of giving kits for them to take home from a party. Let them take the mess home and then their mom gets to be the bad guy and say no way you're making that mess in my house. Sounds like fun.