The lively and popular Three Forks Rodeo is held the third weekend of July. A mid-April high school rodeo also draws big crowds.
The second weekend of August brings Rockin’ the Rivers (406/285-0099, www.rockintherivers.com ) to town. This huge outdoor music festival draws up to 15,000 to hear performers such as Journey, Nazareth, and a Styx cover band (Bonnaroo it ain’t).
Each September, Missouri Headwaters State Park  is the site of the John Colter Run (406/587-4415), a seven-mile dash through the prickly pears commemorating Corps of Discovery member Colter’s 1808 feat of survival when he was stripped naked and hunted by Blackfeet Indians and still managed to escape. Clothing and shoes are permitted on this run.