What is your pre schooler first hobby?

My friend's son loves "being a police" -- he dresses up like one and pretends to look for clues so that he can solve crimes. Reckon this is alot to do with his father being in the police force. His sister, on the other hand, loves tumbling, gymnastics and dancing, a hobby that started after watching a gymnastics competition on TV a few years back. Her parents are planning to enrol her in gymnastics class.