My desktop background:
It's the trail of a line puffer after it settled down. I made sure to pick a spot with pulsars.
The background for the computers at school:
Same general thing, but I used a less wide line puffer so the image would fit the smaller screen. Also, "Press [Esc] to exit fullscreen" would pop up when I logged in for like two weeks until I realized it was part of my background. :/
(If you don't know what I'm talking about, it's Conway's Game Of Life
Space is very spacious.