Want your doorbell to play prerecorded messages or tunes? This hack at instructables replaces the original speaker in a wireless doorbell with a 9 volt recording module.
Most doorbells just make a simple generic tone. But I thought that it would be fun to modify a door bell so that it has a customizable ringtone. That way you can set it to play music or custom greetings. You could make it to scream on Halloween and play carols at Christmas.
Via Hacked Gadgets.