We recommend Montana Whitewater for moderate white water rafting. It's about 30 minutes from Big Sky Town Center.
The Gallatin River has some of the country's best fly fishing. Half day and full day trips are offered.
Ousel Falls is one of our favorite hikes in the area! It's a ~2 mile out and back trail that starts downhill and is good for beginners.
Lava Lake is one of the most beautiful hikes in the area. It's a 5 mile out and back trail that leads to the lake. Expect scrambling and significant elevation gain.