Tall, Tall, Mountain: Pick up two monkeys at the same time
Go to Tall, Tall Mountain as Mario, Luigi, or Wario and pick up the chimp at the top of the mountain. When he asks you to let him go, choose "No" to be able to carry him wherever desired. The other monkey, however, will steal your hat and avoid you. You need to catch him. After this, the monkey asks to be put down and the game forces you to do so. Then take the monkey to the other one and place it down directly where the other one is located. Pick both of them up to now be carrying two monkeys.