Thumbs Up Summer Slam 2026

Thumbs Up Summer Slam is a small summer trail race in Estes Park, Colorado, with only 35 spots and a sunup-to-sundown window. Runners start at 7:10 a.m. and stop at 7:10 p.m., repeating the same 2 km out-and-back on the Thumb Open Space trail as many times as they can. The race begins at a high elevation, with Estes Park listed at 7,522 feet, and each lap adds 540 feet of climbing. The format is simple and demanding: climb out, grab a poker chip at the turnaround, return, then decide whether to go again. The person with the most chips at the end of the day wins. Distance awards are given at 14, 18, and 26 ascents, matching the elevations of Estes Park, Deer Mountain, and Longs Peak. Runners are expected to be self-sufficient, the race is cupless, and finishers receive a custom Nalgene plus achievement pins designed by Space Coyote Tattoo in downtown Estes Park.