Will Drexler submitted this bike/run/bike challenge, which is the brain child of Lamar Felix of Pittsburgh, PA. It is also known as the "Felix Classic":
Rountrip duathalon (bike and run), start bike ride at Point State Park on the Great Allegheny Passage (GAP) trail to Ohiopyle ~77 miles, transition to run, begin run at the "Gate" (mile 0) of the Laurel Highlands Hiking Trail (LHHT), run from trail marker 0 to trail marker 8 (8 miles) then head back to the gate for a total run of ~ 16 miles, transition to bike, bike from Ohiopyle to Point State Park (Pittsburgh) on the GAP trail ~77 miles. Total bike: 154 miles, total run: 16 miles (~4,500' elevation gain).
The GAP trail is a huge biking attaction here in southwest Pennsylvania and the Laurel Highlands Hiking Trail Gate to 8 section is the steepest gnarliest terrain in the area and is frequented by trail runners to prepare for difficult races. This run/ride was modeled after the the Boulder, CO to Longs Peak Duathlon, while not on the same scale, it is what we have.