Via RMGO:
http://www.rmgo.org/faq/

Prohibiting Municipalities. (Denver, Arvada and Breckenridge. Please message us if you know of other municipalities who ban open carry).
29-11.7-104. Regulation - carrying - posting.
A local government may enact an ordinance, regulation, or other law that prohibits the open carrying of a firearm in a building or specific area within the local government's jurisdiction. If a local government enacts an ordinance, regulation, or other law that prohibits the open carrying of a firearm in a building or specific area, the local government shall post signs at the public entrances to the building or specific area informing persons that the open carrying of firearms is prohibited in the building or specific area.
At this website is found a table of all the municipal government names, most of which have websites.
Denver's prohibition on open carry, which is not explicitly stated.
Arvada's open carry prohibition
Pueblo's open carry ban in government or private buildings that post "no firearms." on pages 18-20
(on page 40 of this document is Pueblo's law against weapons -- open carry only, as state law governs concealed -- possession in places that sell alcohol)
Castle Rock has an open carry ban that extends to nearly every city-owned location. Castle Rock City Ordinance 9.04.165

And:
The Meyer decision: http://www.rmgo.org/alerts/2004-denverruling.htm

Points in the decision relevant to this thread:

1) Colorado state law allowing loaded handgun in vehicle without CCW permit is legal, including within Denver

2) Denver law prohibiting open carry in Denver is legal.