The Medora Musical is a different show each year, a mix of singing, dancing, and fun in an outdoor amphitheatre with a little Theodore Roosevelt history thrown in.
My kids loved every minute of it. I was concerned that it would be hard for them to enjoy it, since it starts at 8:30 Mountain time, which is 9:30 for those of used to Central, but they did just fine. Staying right in Medora instead of driving 20-30 miles to a nearby town would be a good idea, though.
Also, it gets cool in the evenings, so wear warm clothes and bring blankets with you. We wore jackets over sweatshirts in addition to being wrapped in blankets.
If you can, go on a Wednesday when kids are free and there are special kids' activities going on around town as well.
The Medora Musical was the kids' favorite part of our 8-day trip around North Dakota.