Crepe paper the door for Christmas so they have to bust out when they wake up. Santas elves did this to make sure they stayed in their rooms. - I need to remember this in the future! Good idea for a Birthday morning too!
Magic Elf Seeds--Use tic tacs and sugar. The kids plant the 'seeds' before they go to bed and when they wake up they are candy canes! Elf on the Shelf could leave the seeds for the kids to plant that night.