Stuff like, notice an amazingly tacky display of lights and have to turn around and drive by slowly and gawk. And he reversed the car just so I could get a better perspective shot without me even asking, he just knew.
Of course, after that we had to take a closer look at all the other neighbor's lights. Especially, the random blinking trees that I was certain were cued to music.
Then we went home and did what all old people do in that situation: eat cookies and stand around and talk.