Back when `/dev/mem` was a thing in default kernels (now you need a special config, or a module), I enjoyed `cat /dev/urandom > /dev/mem`. That would usually bork things pretty quickly, so then I would set random offsets with `dd`. Fun times.
It picks a random device on your system -- ram, video, bios, etc -- and writes a random number of random bytes into it and then sleeps for a random amount of time.
