If you run Windows on a ThinkPad or similar machine, and you ever wished you could have precise pixel-by-pixel mouse movement from the keyboard home row, try it out.
I think it's also a good example of some fairly well-written AutoHotkey code. (Please ignore the messed-up indentation in the SetKeyMap function... Time to add a .editorconfig file!)
I originally wrote JKLmouse as a native Windows app in C using keyboard hooks. But when I saw that I could do the same thing in AutoHotkey it was a big improvement.