Play the birthday song using musical notes. Change the notes so you can play your favorite song. Search for the musical notes of your song on the Web. Search for "midi notes" to see a mapping of notes like C# to numbers. You could even make the program take any input of notes and play it.
music and instruments, simple loops, delays, simple costume handling, simple events, screen bounds, simple motion, direction and turning, advanced costume handling, miscellaneous,