Across the street from Boulder's new Twenty Ninth Street mall, you'll find the relatively recent Harpo's. With high tables, lots of TV's, and a big sheltered patio, the place competes with The Lazy Dog for the title of Boulder's Sportsbar.
Beer selection is great, with a fantastic variety of beers on tap. Food is pretty good, with usual sports bar favorites prepared a little healthier for the local market.
Service is friendly, although not always fast, and you'll find the customers to be mostly guys hanging out with friends.
If you happen to be in the area, it's an obvious choice. But if you're coming from out of town and want a sports bar with great beer and good food, I recommend you head downtown to the Lazy Dog.