The Gift of Time. I absolutely adore this idea. I wish I had known about this the very first year that I was married as I would have used it as a wedding gift (although it would make a fabulous birthday, anniversary or Christmas gift now)!
Every year starting on Feb kids wake up to a new heart on their door that says something you love about them. By Valentine's Day they have 14 reasons and their gift is waiting when they wake up:) That sounds like a super cute tradition to start!
Tic tac toe - kids write a "O" on the marshmallows and Elf will play his "X" every night. Good way to take up a couple of days! Could accompany with a note. Or just fun way to do tic tack toe with your kids if you don't do elf on the shelf