This one is a memory. Lori259 mentioned baking cookies with the kids and leaving some out for Santa. Well, when I was growing up, my Dad worked for the post office and he got off around midnight. We would leave out the cookies, and when Dad got home around midnight, he would eat "Santa's" cookies.
Years passed and us girls were all teenagers. We had an old Labrador retriever named Moses, and he was so old and stiff that he was allowed to sleep inside at night. Well, we made the cookies as usual and set them out on the coffee table for Santa/Dad. When he got home from work, he was disappointed; his girls had grown up and there were no cookies. The next morning, we pieced it together; Moses had eaten Santa's cookies!
My boys are both all grown up now, but they usually end up spending the night here on Christmas Eve. I always wake them up the next morning by saying, "Santa was here! Santa was here!"