Not quite on topic, but as for PC speaker tricks: I once found if you control the tape-interface relay switch on a BBC B (or BBC Electron), from a BASIC loop, y

Not quite on topic, but as for PC speaker tricks: I once found if you control the tape-interface relay switch on a BBC B (or BBC Electron), from a BASIC loop, you can make it click really fast and make silly noises! Doesn't work in an emulator though.