Ctrl + Alt + ← [left arrow]

Dutifully reviewing my outlines for the upcoming bar exam, I wished to highlight a certain portion of text that was practically begging to be painted yellow to ensure inculcation of a legal principle warranting careful scrutiny during future review. I recalled that there is a way to highlight text in Word without making my poor, weary mouse hike all the way up to the Quick Access Toolbar and click the Highlight icon for me: a "shortcut key" as they call 'em these days. I thought I had pressed Ctrl+Alt+H to highlight the text but, to my horror, my computer's display flipped 90 degrees counter-clockwise!

It turns out I had pressed Ctrl+Alt+← (I was using the left arrow to try and select the text I wanted to highlight). Try it! It'll blow your mind. But remember, press Ctrl+Alt+↑ [up arrow] to get your display back on the up and up, as it were.