supa is right. unnet.net is probably the most active denver board, period. everyone from colorado's finest, lighting crews, promoters, venue owners, etc. the owner of said board is one of colorado's best djs (in my opinion) and a stand-up guy; dj nommo aka michael.
unnet is a great place to waste-away your afternoon. like supa said... thick skin and a sense of humor are required to join this group... its all in good fun.
http://denverforums.com/ is another board for denver... far less active than unnet.net, but still a plethora of denver info.
http://groups.myspace.com/coloradoraves is myspace's active group for local party discussion.