There's more to do on the slopes in Park City than just ski. The newly opened Flying Eagle Zip Line is a great way to end a day of skiing, or keep a little amused while the big kids ski. Children need to be at least 42 inches tall and accompanied by a "responsible adult" over 54 inches tall. It's $14 for the big person and $7 for the little one. For this you get two high flying rides up the mountain.
It's truly not scary and probably doesn't even count as a thrill for teenagers, but if you're six and just tall enough to go, it's the best time you've ever had in your life.
You can find more information at Park City Mountain Resort.