Well sort of – I have never seen or experienced this in my years of flying. I was on UA 233 from MCO to ORD yesterday (3/2). Sitting in 2C watching the people meander by when a family boards. Mother was first followed by a 6 year old girl and an 8 year old girl. The girl dropped her carry on which startled her 4 year old brother who was behind her. Suddenly, the captain says “Sonny, come here and sit in my chair” and points at the boy. He asks if his sister can join him and the pilot invited them up front as well. The pilot sees dad walking on and asks for his camera which the father gives him. He must have took five or six pictures and next thing he tells the co pilot to get into the pictures and then starts explaining everything to the kids on how to fly the plane and what certain instruments do. I can see one of the girls holding the headset and suddenly the PA system comes on. She says “Mom, I am upfront driving the plane”. Other passengers are looking around like who knows what is going on. After about four minutes the fun ends and the kids head back to their seats.
Granted the pilot did not have to do this but I thought that it was an absolutely fantastic gesture on his part and something that those kids will remember forever hopefully.
For all of the complaining that people do about all of the problems with UA, it was heartwarming that this pilot went out of his way to make those kids feel on top of the world at that moment. It was truly the highlight of my day.

PS – After everything calmed down, I walked up to the captain and gave him a GTEM. I told him he deserved a few more for what he did.

^^^