Bozeman is a great place for a family trip!  

Start with the Children's Museum of Bozeman for the under 12 set, it is just a couple blocks off Main Street on Willson Ave., so it is easy to get lunch afterwards in Downtown. Don't miss the shopping in the area including the Emerson Cultural Center and Rocky Mountain Toy Company.  Head out Willson to the Museum of the Rockies for a taste of homestead life, Montana Dinosaurs and a world class planetarium. Great food is also located just across the street from MOR as well.  Gotta keep the kids fed!  If you have older kids, start with MOR and don't miss the American Computer Museum and the Pioneer Museum for history.  

There are lots of parks and outdoor activities too!  The Dinosaur Playground is located on the west end of Bozeman at Oak and Davis. There are several climbing boulders located around town on the Gallagator trail and at the Bozeman Ponds (just west of the Gallatin Valley Mall). There are Farmer's Markets on Saturday at the Fairgrounds and on Tuesdays at Bogert Park.  Bogert is also home to an outdoor swimming pool (open June - Labor Day at 1pm), tennis courts and a nice playground.  There are also Municipal Band Concerts at the Bogert Stage every Tuesday evening during the summer.

For the more adventurous, head out south of town on 19th avenue to Hyalite Canyon which is full of long and short hiking trails. Pallisade Falls and Grotto Falls are handicapped accessible and stroller friendly.  The trail at Grotto Falls continues on to several more waterfalls on the way to Hyalite Peak.  North of the city there are many hikes in the Bridger Mountains, including a hike that starts at Fairy Lake and goes up to the ridge and Sacajawea or Hardscrabble Peaks.