Spot the giant M emblazoned on the side of Mount Sentinel, and then follow the trail that winds up its side in the early morning before the college kids wake up. The trail is less than a mile, but it's steep, which is why there are plenty of benches along the way. But once you're at the top, you'll be rewarded with a vista that includes the entire Missoula Valley, Rattlesnake Wilderness area, and the town below.
Practice your back casting on one of the three rivers that converge in Missoula: the Clark Fork, the Bitterroot, and the Black Foot, the latter of which became famous in the film A River Runs Through It. No matter what your skill level is, you're best off hiring a guide from Grizzly Hackle (from $465 for two people, including lunch) to take you out and find the best spots to head depending on the time of year. Most fishing in the area is subject to catch-and-release laws, so don't expect to keep your prize, no matter how impressive.
Get wet on a whitewater-rafting adventure with 10,000 Waves, with trips from scenic floats ($70 per person for a half day; full day with lunch $85 per person) to overnight full-throttle paddles through raging rapids ($295 per person, two days). Either way, you'll be navigating the waters where Lewis & Clark once charted. If you prefer to stay dry, see their trails on horseback with the equestrian outfitters at Dunrovin Ranch. Their stables are filled with Tennessee walking horses, whose steady stride makes for a very smooth ride along the Bitterroot ($110 per person).