Ctrl-alt-arrow key doesn't just turn Explorer a different direct, it puts your entire screen in a different orientation. If you flip it upside down, then move the mouse up, the on-screen mouse goes down. It's fun to practice it enough to be able to do it no problem, then act as if nothing is the matter when other people see it.
Another fun set of keys to press is left shift-alt-print screen. High contrast! Just push the set again to change it back.