But over time, it's expanded to electronics. I remember one time, my sister was probably 4 or 5 and I was 8 or 9, I came into my room and she was deleting everything off of my Gamecube memory card.
Since then, she's reformatted my laptop hard drive, left my PS3 game disks outside of their cases (often simply laying them on top of the PS3, how lazy), and gotten crumbs all inside of my tower computer.
So share your stories of when you gave your sibling too much freedom around your stuff, and ended up paying the price.