Kayakers run the slaloms in Clear Creek, Lefthand Canyon, and the South Platte, but Boulder Creek from within Boulder Canyon midway into the city is one of the locals' favorites. Water in the creek can create Class II-III rapids when summer conditions are right. If calmer waters suit your watercraft-handling style, you can take a canoe to or rent one at the Boulder Reservoir and paddle about while taking in great views of the Rockies. 6 mi northeast of downtown. Drive northeast on Rte. 119 and turn left at Jay Rd. Turn right immediately onto 51st St. and drive on to sign that marks entrance station. 303/441-3468. $6.
Alpine Sports (2707 Spruce St. 303/325-3231 or 877/325-3231) rents touring and sit-on-top kayaks, canoes, and rafts for $25-$35 per day. Gear packages, which include helmets, oars, and life preservers, rent for $25 a day. Multiday discounts apply.
Boulder Outdoor Center (2525 Arapahoe Ave., Suite E4-228. 303/444-8420 or 800/364-9376. www.boc123.com) organizes group rafting trips to rivers on the Front Range and group kayaking instruction.