One of the few times I ever saw Mom nearly lose control laughing was when we watched the movie Better Off Dead the first time. The scene where the main character remembers the first time he met the girlfriend and they are sitting at a picnic table. One brushes their nose and the other thinks it's a hint that there is something hanging off their nose so they then brush their nose off, which leads the other to rub their nose even harder, and on and on and on. It's likely the funniest scene in the entire movie and Mom laughed so hard at it. We all were nearly falling off of the couches laughing.
Every time I watch that movie, when I get to that scene, I laugh even harder at it than it probably deserves because I always think of Mom. :D