Strange is BAD ASS! Not a fan of Breckenridge, although I know some people who are. If you're looking at the whole state, we've got O'Dell and Avery which are both amazing. There's really too many to list, but I know I'm going to keep trying to find them all.
I've noticed nobody has mentioned Tommy Knocker Brewery, although it's not in Denver. They have a beer engine and it's the single greatest thing I've ever seen! Also Wyncoop has great beer and they too are making "real ale" and serving with beer engines.
Besides those 2 I have to say Oscar Blues, Dales Pale Ale is awesome!