Just wanted to share some good experiences I had in the Boulder/Denver area last weekend:
Beau Jo's Pizza: Huge gluten free menu, including appetizers, beer, pizza, sandwiches. Wait staff was knowledgable and food was tasty. Had good gluten-free garlic bread. We went to the Arvada location, but there's several in the area.
Hacienda Colorado: Large gluten free menu. Chips are made fresh in a dedicated fryer - was really nice to be able to eat tortilla chips w/salsa and guacomole for once! They also make fresh corn tortillas, which were really good. Our waitress was a little lacking on gluten free knowledge, but the manager was able to answer all our questions. We went to the Westminster location, but there are others in the area.
Hapa Sushi: Large gluten free menu, and they'll bring gluten free tamari if you request it. The only problem here was that they brought out my sashimi on the same plate as my sister-in-law's order, which had gluten in it. I gave the sashimi to my husband and stuck to the other rolls. I didn't get glutened here, but if you go, you may want to stress keeping things separate to the staff.