My alarm system has triggered in my room for no (apparent, or should I say apparition?) reason 2 or 3 times in as many years. There is a camera too but nothing can be seen. Unfortunately, the system calls out to the alarm company and police so results in a flurry of calls that nothing is there, and I'm not a hostage or being molested.
One time I think it was a mouse (or maybe a pissed off rebel) who knocked over my drum, but the mice have been sent to Valhalla so that doesn't explain the other times?