How do you know it's time to stop writing the paper for your upcoming conference and go to bed?
When your monitor display suddenly turns sideways. As in, the whole thing: task bar, text, everything.
It turns out that the video card in my new desktop machine has this capability -- if my old one did, I never encountered it. If you purposely (or accidentally, as in my case) hit Ctrl-Alt- arrow key, your display goes wacky. But then you can toggle it back.
But there's nothing quite like trying to read stupid Help screens sideways -- to no avail -- I Googled the problem after a few minutes and found my answer quickly.
But now I have a neck crick. And I'm tired anyway.
p.s. There really should be a rule that conferences can't be scheduled during the first month of classes. I'm so not ready to shift gears all of a sudden, since I have barely gotten into teaching mode.