Some of the coolest stuff are the things like the wallpaper cheats:
Besides programming, these are great backdrops for institutional PCs, classrooms, or your old parents who need help hacking into Joshua from War Games.
I think a great lesson here is better use of your desktop wallpaper. At work, we have a generic background but it also contains 30+ regional customer support numbers for our global clients. You can create your own cheatsheets with your favorite photo/drawing editors and overlay text.
Here’s another one I like, a Firefox shortcode sheet:
Now if only I could find a full set of TARDIS controls…