Hedwig's Theme on a homemade punch card. Some parts sound strange, but it was the best I could do on a diatonic music box.
You can get one at sites like thinkgeek or grand-illusions.
If you want to know it works, check out synthfiend707's tutorial h
by Dorothée BABOU
by Swirly Cinammon
by Sangi Creations
by Brian Hinson