Feel free to visit the amphitheatre to walk around and take pictures. If you are feeling extra adventurous, try out a workout on the rocks! There are multiple short hikes around the rocks as well.
Get a group together and tour Coors Brewery. Learn a little bit of the history, see the brewing process, and most importantly: drink beer! Tends to be a popular attraction with long lines but definitely worth it!
Just north of downtown Denver is a trendy area full of breweries and bars. Prior to Eric getting diagnosed with Celiac, we spent a lot of time at some of these breweries: 10 Barrel Brewery, Epic Brewery, Odell's Brewery, and Ratio Brewery. There are SO many more but this is a great start.
You can't go wrong with a hike in Boulder! Be careful if you're coming from sea level because the altitude is no joke! There are plenty of shorter hikes to get outside and enjoys the views!