When I was about 10 I decided to set up an imaginary business selling homemade stationary (notepads made of scrap paper!). It was a great way to entertain my younger sister making them whilst I programmed a full POS and inventory management system in BASIC.

Needless to say, my sister got bored of the idea long before I did. 20 years later I still use the same name as our imaginary business for any freelance work!