Had years of fun with and Annoyatron, it would make random noises or set it for one noise at random times. You find a lot out about your coworkers.
One sound was a guy scratching saying "hey let me out of here" The office lady really thought she was hearing voices and checked herself into a mental health facility. Come to find out she was really crazy but the voices didnt help....
I put it in my bosses office with a "cat meow" on random, I put in on the backside of his big oak desk. He stripped his entire office, chairs, books, computer, book shelves, even took the light fixture, wall outlet and drop tile ceiling down.
We had a fabricator in a well ventilated room. I set the Anoyatron to a random beep, heard nothing for 3 months. Figured it was too noisy in that room to hear this tiny device. After that we asked the guy one day "did you hear that" The look of excitement he had, we heard it!!! He whipped out his notebook and had pages of date, times ect that he heard the beep. Come to find out he really liked meth.....