I bet you thought your cell phone was the only thing with custom ringtones. Jason Poel Smith wrote in with his Doorbell with Custom Ringtones that he built using a Radio Shack 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.”