[novaleaf]

Rocksmith is nice, but it's learning curve is too steep, especially for little kids. wish there was something more gentle I could use for the kiddos!

[aequitas]

Maybe try Yousician, I used their Android App before I stumbled upon Rocksmith. Didn't play it for long but I think it will be more suited for kids. I believe you can get a half hour of free practice every day and unlimited when buying the Pro.