My TI-99/4A was my first computer. I started programming when I was five years old, typing in code from a variety of sources and learning until I could roll my own from scratch. I used it to create images, small games, sounds, and music.
When my high-school biology class made models of DNA, they used gumdrops and toothpicks, wooden balls and dowels, the usual. I worked for days to code a demo that showed DNA unzipping and replicating. I _earned_ my A+ for that project.
Good times!