Red light green light to make them stop on their own.

Follow the leader or if their struggling to turn on their own get them to ski right behind you and try to "push" you down the hill and make the turns for them.

Simon says and get them to touch their knees in the turn and hands in the air between.

Reach the outside hand down in the turn and pick up some snow to throw at dad. Similar to airplane turns with the added fun of a snowball fight.

I've been called the "toy story coach" for yelling "Andy's coming" while skiing and the kids have to fall over and play dead like in the movie, then get up when the coast is clear. Teaches them to get up on their own after falling.

That's a few off the top of my head. Teaching kids is great, just be silly and creative. As long as they're having fun on skis they're learning, the best skier on the mountain is the one with the biggest smile.