Not sure if you looked here, but if you click on the Forums button at the top of your screen, and scroll down towards the bottom, you will see a section for local reef clubs by state. Click on Colorado and see if there is anything there of interest. It doesn't appear 2 of the 3 are very active, at least here on R2R. That doesn't mean they may not have their own site though. It also doesn't mean this is an all inclusive list of clubs in Colorado.