Just one? That's a tough choice. I have so many wonderful childhood memories, particularly with my maternal grandparents and my numerous cousins on that side of my family.
I remember Sunday afternoons when relatives would drop in at Granny and Grandpa's house at whatever time was convenient...we'd eat, talk, play, listen to America's Top 40, etc.
I remember holidays when everyone knew food would be on the table at noon, and we all tried our best to be there by then.
I remember New Year's Eve when an entire group of cousins would spend the night together. We'd watch New Year's Rockin' Eve, I'd get teased about my crush on Barry Manilow (who was part of the yearly tradition back then), and then we'd watch horror movies all night long, or until we all fell asleep in front of the television.
I remember "fair week" when Granny would have a bunch of us staying with her for the entire week---working in the house, garden and/or yard during the day to earn our way to the county fair every evening and all day on "kids day."
And those are just a few highlights off the top of my head!!