Want to learn to right yourself if you flip a whitewater kayak? CU's Outdoor Program offers Kayak Roll Clinics and other essential whitewater skills courses in the Clare Small Pool for extremely reasonable prices. Check out "water activities" at http://colorado.edu/recreation/outdoorprogram/ to learn more.
Summer gets hot in Colorado. Though it's winding down, there are probably plenty of hot days ahead, which means you'll probably want to play in our great state's many rivers and lakes.
Average temperatures for September in Colorado still hang in the 80s, and after heating up all summer, most lower elevation lakes and rivers are very warm.
Get wet and chill with some of these options for nearby water-bound recreation:
Stand up paddleboarding, or SUP, is so hot right now.
SUP is great for relaxing, racing, sunrises, etc. You can make it as intense or chill as you want.
Most intro to paddleboarding instructors will emphasize that your core should be doing most of the work as you paddle, not your arms, which means that your abs and obliques will hurt the next day if you're not used to it. Try paddling from your knees at first if you're nervous, but once you get the hang of it, don't be afraid to fall in on purpose once or twice. (That's half the fun, anyway.)
You can rent paddleboards from two places at the Boulder Rez, or you can buy your own for around $1,500, womp. Rocky Mountain Paddleboard, http://rockymtnpaddleboard.com/, rents boards in the early mornings and evenings for $20 an hour. You can also try one of their SUP fitness classes, like SUP yoga or bootcamp.
You can also rent paddleboards from the Boulder Reservoir's boat house (https://bouldercolorado.gov/parks-rec/reservoir-boat-rentalsboat-house) for $16.50 per hour. Boat house hours are Monday through Wednesday, 11 a.m. to 6 p.m. and Thursday through Sunday, 10 a.m. to 6 p.m.
Tubing might be the most popular activity for Buffs who stick around Boulder through the summer. We don't have numbers to back that up, but we sure see a lot of you out there on Boulder Creek.
If you're not into the spectacle of tubing Boulder Creek, which runs right through the edge of downtown Boulder, check out the Saint Vrain River near Lyons or Longmont if you want something a little more private.
To rent a tube, check out Colorado Water Sport, http://whitewatertubing.com/, in Boulder, which will rent you single and double tubes starting at $16.
Some seasonal tubing advice: depending on snowmelt, spring tubing can be super dangerous. Watch for high water levels in the spring, and conversely low water levels during the summer, which can lead to you dragging your buns over all sorts of creek rocks and plants. Ouch.
If you stick around Boulder next summer for a job and you're feeling particularly tubey, join in on Tube to Work Day, which in 2013 saw 19 Boulder commuters tube to work in their suits and business-casual best.
Paddling (boats, not boards)
Want to learn to kayak like they do in the Olympics? Check out the Lyons Kayak Club, which provide instruction and support canoeing and kayaking in the Front Range. The club works closely with the Lyons parks and recreation department, which maintains the Lyons Whitewater Course in Meadows Park -- home of the early-summer Lyons Outdoor Games.
Check out http://rafting-colorado.net/, which offers a complete listing of guided raft tours throughout the state. The most popular rafting spots are along the Arkansas River, which you can access off I-70 or southern I-25.
Short rafting trips are pretty reasonable -- half-day packages start around $50 -- but for bigger trips, rafting can get pricey. Multi-day trips can run you up to $800.
--Follow Sarah Kuta on Twitter: @SarahKuta.