Stop by washington park in denver on a saturday or sunday anytime from noon to 8 pm...make sure you are ready to play basketball (monday and Wednesday night for best bball). Cool tennis courts and beautiful open space for any sport. Make sure you make friends and join a volleyball or spike ball game! Since you are headed northbound (this tip is for before reaching denver) stop by manitou springs and conquer the incline (about .8 of a mile in one direction, up) or explore San Isabel Forest near Colorado springs. Once in Denver, check out union station downtown, and larimer street for fun bar hopping adventures and brilliant craft brew. Stop by horsetooth on your way out and north in fort collins (but solid grounds coffee shop to say whats up before you leave the denver metro area). Safe travels!