If you’re around Aspen Sept. 18, you should definitely check out this new event helped created by part-time Aspen resident Lance Armstrong. The Aspen 50 was conceived by the Tour de France winner in an effort to raise funds for the Roaring Fork Mountain Bike Association and its work on trails.
“While this inaugural ride is not actually a race, you can expect some truly fast riders to be leading the way as soon as the pedaling starts.” -RFMBA Executive Director Mike Pritchard
The course is actually pretty gnarly. It’s 54 miles long and riders will have climbed 7,264 vertical feet upon completion. 
Registration for the event is free but participants will be asked to purchase an annual membership for the mountain bike association. Entries are limited so sign up ASAP if you’re interested. REGISTER HERE.
If you’re an Aspen lōc-dog you might understand this detailed course description from the website:
“The event starts with a climb up Smuggler Mountain Road and then hits the Hunter Creek Cutoff to the Iowa Shaft Trail, all popular routes on the Smuggler Mountain-Hunter Creek Valley circuit.
Riders will make their way across the upper bridge in Hunter Creek Valley, head upstream and climb the Hummingbird Trail to hook into the two roads that lead them to Four Corners. From there they will take the singletrack trail descent to Lenado on a route some call Tinpot.
From Lenado, the riders will take country roads and a paved path to get to the Intercept Lot at Brush Creek Road and Highway 82. They will make their way to Cozyline for the climb into Sky Mountain Park and traverse on Skyline Ridge Trail before descending on the always-thrilling Deadline Trail.
They will use Highline Trail and Tom Blake Trail to make their way to the Snowmass Village Mall, and then use roads to access Rim Trail South, Rim Trail North and the descent to the recreation center. They will follow the Brush Creek Bike Path to make another climb up Cozyline, then a descent on the Airline Trail. The paved Owl Creek Trail and soft-surface Buttermilk Connector will get them to the end of the ride — nearly 54 miles later — at the Buttermilk parking lot. Participants will climb 7,264 feet over the grueling course.”
….good luck out there if you decide to participate!