Registration The City Of trees Marathon Association Inc. uses www.BlueCircleSports.com for race registration. Provided below are the links to the Registration Pages on BlueCircleSports.com Freezeout Challenge Click Here: FOC-BCS Les Bois 10K Click Here: LB10K-BCS Fit For Life Half Marathon Click Here: FFL-BCS Payette Lake Run Click Here: PLR-BCS City Of Trees Marathon Click Here: COT-BCS