I created a little script that ran on startup that would wait a random amount of time between 5 and 15 mins and would just hit the left key once. I dropped it on a dev's computer when he left it unlocked and forgot about it. After weeks of torment, it activated while he had a YouTube video so he figured out it wasn't his fault. He was convinced it was the keyboard and started harassing IT so I had to come clean.

Jokes on me though, every time there was any quirk on his computer, server, or with his code he blamed me and didn't believe me.