High Quality Content by WIKIPEDIA articles! The Rocky Mountain Showdown is an an American college football rivalry game played annually by the Colorado Buffaloes football team of the University of Colorado and the Colorado State Rams football team of Colorado State University. The winner of the game receives the Centennial Cup. The series began in 1893 and was played annually (with a few exceptions) until 1958. The series was resurrected in 1983 and played periodically until it was cemented as an annual rivalry in 1995. Colorado leads the all-time series, 61–20–2. The Colorado Buffaloes are in the Pac-12 Conference, while the Colorado State Rams compete in the Mountain West Conference.