Reindeer food is oatmeal, glitter and colored sprinkles, or any other food decoration you want to put in. Its easy and my step-daughter who is 8 loves to make it then put it out on Christmas eve.
I’ve also got sliegh bells and I or someone else who was in on the fun would sneak outside right before they went to bed and would run around ringing the bells so it sounds like Santa is right around the corner :D . The kids don’t put up any kind of fuss about going to bed. But make sure you tell them that they can’t look out the window or Santa will know they are not in bed asleep and just keep going. Works every time. My son and daughter remember this from when they were little and intend to do they same for their children when they have some. ;D