Here is another fun way to irritate & annoy people. This time the noisemaker uses an ATtiny2313 to generate random noises. The website has all the code & schematics so you can build your own Sanity Nullifier.
The device beeps a short beep of a very annoying frequency in random times. The time between beeps is anywhere within half an hour to nine hours.
Make your own Sanity Nullifier
Read about a Simple noisemaker annoys your neighbors