This took almost no time to put together. The “speaker” is a Tim Hortons cup with a cheap piezo glued to the base. What makes the Arduino sing is the Tone Library running its RTTTL demo sketch, with the anthem itself pasted in from a rather old Nokia Ringtones library.
Update: Here’s the code, such as it is. It’s just the Tone/examples/RTTTL code with the tune data pasted in. I’d been programming Arduino for about a year, so that was a semi-major achievement for me: