Depends where you're staying. On the south end of town, check out Felt. It's a full-service room with a few Diamond tables, several more old Brunswicks and a bar and good restaurant.
The traditional old-school room is called Hank's (formerly the Family
Fun Center). Their equipment is still satisfactory and some good players frequent the place. This was the room that was on every road man's map when pool was in its heyday.
Enjoy yourself in Denver.