One of the things about this time of year that comes up more often than not, is the odd time of eating at holiday gatherings. Your main meal and time dedication to eating for the day is over often by 7 pm, the time that you'd normally eat dinner. Hence the need for an after-the-gathering snack.
Unless you're the type who hits the hay at 9 pm, and we are most definitely not, I suspect it's a commonality. Growing up in my family, it was cereal. Our cereal cabinet was stocked like Jerry Seinfeld's and was the learned go-to if such noshing was to occur.
I've begun taking this question of 'what's for snack' as an opportunity to make something I love but don't make nearly enough: popcorn!