Thinking something like

  1. Hot cross buns in Ab major
  2. Mary Had a Little Lamb in A major
  3. Twinkle Twinkle Little Star in Bb major
  4. Do-Re-Mi in B major
  5. Amazing Grace in F major

And there's Level One!

...or should there be more levels?...

And I guess Do-Re-Mi isn't exactly traditional.

I know there are scads of other traditional songs, and it would be cool to feature some more obscure ones. Nursery rhymes etc.