My cats are not trained to do any tricks. They go to the bathroom in one designated spot; that is the only trick I ever require a cat to perform.
Prudence has a new game where she runs out the dog door to the back yard like she has somewhere urgent to be, then bolts to my bedroom sliding glass door and cries pitifully to be let in the house. If I let her in she acts as if I saved her life and is very affectionate and makes happy noises for about five minutes. Then she tears off running to the kitchen all of a sudden, and runs out the dog door into the back yard, then heads directly to my sliding glass door.... I did not train her to do this brilliant stunt. But she has me trained to leave the sliding door in my room open most of the time now. When the door is open, she will run to it and plop down outside, facing into my room and stare into the house. After about ten minutes she will come through the door, turn around and lay down facing outside and watch the back yard for another ten minutes. She will alternate these positions until it's time to run the loop through the house again.
I'm pretty sure my cat is a genius.