So my kiddo was watching TV one day and all of the sudden he jumped up and starting singing and doing the whole dance routine from the Fresh Beat Band. He's 3 and I had never seen him do anything like this, and it certainly wasn't prompted by me! Guess he's got my musical genes though.
Then last Sunday I volunteered in his Sunday school class and found out that they have performers who lead them in similar upbeat songs with elaborate dance moves. Alex was really into it, but at least that explains where it comes from.