As a child, Gran always gave us each a very special gift on Christmas Eve. Three boxes all wrapped and tied together with one big bow. The first was always pjs or a gown with slippers, the second was a stuffed animal to cuddle through the night and the last was always a good hardback book- usually about Christmas or giving, or something she knew we'd enjoy.
I followed through with this tradition for my own kids and they look forward to it every year.
We open them up after midnight mass, before going to bed.

PS- New jammies make all our photos look better, cuz otherwise, we mostly sleep in tshirts or mismatched pj sets!