I haven't lived in Colorado for 11 years, but I'm sure there are a few things that are the same.
Lodo is fairly touristy, but that's where much of the nightlife is. Check out the Wynkoop Brewery. I don't know if El Chapultepec is still around, but when I lived there, it was my favorite place to hang out and see jazz.
Do you have access to a car? Denver is fairly spread out, and you need a car to get places. My favorite restaurant in the world is a Vietnamese restaurant named New Saigon. It's on Federal Blvd a few blocks south of Alamosa Blvd. Delicious and cheap.
There is another strip of bars and restaurants on S. Colorado Blvd south of Speer Blvd. They are a bit more hip than Lodo.
Check out the Denver Museum of Art. There are a few other museums nearby, the Capitol and the Denver Mint. It's a popular area for bums, but they are harmless.
There is a really good pizza place in Edgewater, but I don't remember the name. Ask a bartender.
Avoid anything with John Elway's name on it. The man was my childhood hero, but anything he touches will be super expensive.
Go to Boulder and check out CU and Pearl Street. It's the most beautiful view.
Drink local beers - Left Hand, O'Dells, Avery and Fat Tire. Avoid Coors, Breckenridge, Boulder Brewery and Flying Dog.
Have a great time. It is a great town.
I am homesick now.