I grew up playing about 15 instruments and the way that I was able to accomplish that was by cutting my classes, hanging out in the band room all day, and going from one instrument to the next to the next, until I learned how to play everything by ear.
I have four kids; three girls and a boy. The oldest girl is 13, and has her own social life now, so there's a bit of begrudging cooperation there. It's tough.