On our way to Yellowstone, we stopped off at the "Yellowstone Bear Country" in Rexburg. It was the day before their big winter hibernation festival (which would have been fun to see) but it was much less crowded.
In Bear Country you get to drive through a bear habitat. The bears wander around, play and sleep while you drive just feet away from them. We've heard that the bears can actually paw at your car, or stand up on it if you stop. So, we did our best at not stopping and keeping our windows up. Just like they told us to. But we may have taken a picture or two with our window down. Oops.
The petting zoo was a lot of fun for the little girls. They took a million pictures and had a blast petting and feeding the animals. The pig was my favorite but he didn't really care for people.
I would definitely recommend it as a stop if you are heading through Rexburg to West Yellowstone. It was a great break from the drive and we saw WAY more bear there than we saw in Yellowstone. (And just for the record, 1 would have been more than we saw in 2 days at Yellowstone).