The All-Out Spring Fever is a spring race held on the Ralston Creek Trail close to Golden, Colorado. Runners can choose between 5K, 10K, and half marathon distances. The courses run alongside Blunn Reservoir in Arvada, offering views of Table Mountain and the Colorado foothills, giving it the feel of a foothills trail run rather than a city race.
This event is organized by All-Out Multicourse and serves as the spring complement to their Kooky-Spooky series. The race features a bee mascot named Buzzby, benefits the People and Pollinators Action Network, and offers a chance for participants to qualify for a BOLDERBoulder starting wave. A virtual half marathon option is available for those who wish to complete the distance remotely.