Let me present my 2-year-old's second favourite music, after Van Halen - Jump :

https://www.youtube.com/watch?v=u8ccGjar4Es

This is amazing, I almost want to have more kids so I can have them love this song.

I'm tempted to slip it in at a rock night.

Lots of things stop working after 4. (5 here)

One very important limitation: you run out of hands.

No, but if I say the exact number I'm even easier to pin down.