Smash Bros and Wii Fit are great, not played that bowling game (the bowling on Wii Sports is fun mind you).
On Wii Music, you move your hands like the instrument and whatever speed you want and the song autoplays itsself perfectly and there is no skill involved. You can play drums OK-ish with the balance board as a kick pedal, but there are no tasks as a drummer, just a drum set to piss about with.
On her birthday, upgrade her to Rock Band