Denver's secret cuisine-wise is Mexican Food (or more precidely, New Mexican cuisine). Eat green chile early and often. Green chile is a gravy-like sauce ladled on top of Mexican dishes like burritos, chili rellenos, etc.,. It is made from roasted green chili peppers grown in Colorado and New Mexico. http://www.westword.com/restaurants/the-ten-best-places-for-green-chile-in-denver-2016-edition-7591364
There are also a plethora of BBQ and Soul Food places in an area called "Five Points":
Denver has a pretty vibrant music scene also. If y'all can grab a concert at Red Rocks (might be too late for outdoor venues), do it. You can also just drive out to Morrison to see the amphitheater itself and try "running the steps":
Speaking of exercise, Denver has more dedicated bike paths in the city than probably any city of its size. Renting a bike and riding around is a great way to explore the city. https://www.denver.org/things-to-do/sports-recreation/bike-trails/
The Denver Zoo and Denver Botanic gardens are pretty good to see also.
Within 30 minutes of Denver are some great day hikes.
Boulder, Colorado gets a lot of derision (mostly deserved) for its granola lifestyle, wannabe hippie lifestyle, etc. ,. But it is still a cool place to visit. It's a university town, after all, and will remind you of Baton Rouge in many ways. If you head out that way, there are some cool things to see, like the lobby of the "Boulderado Hotel", a historic hotel from Colorado's wild west days:
If you are meeting up with your USMC buddies for a "guys day out", there are limited stakes gambling casinos in Central City, Colorado. If you have a 4-wheel drive vehicle, go to Central City over the "Oh My God" road that connects Idaho Springs to Central City. Idaho Springs is about 35 miles west of Denver (in the mountains) off of I-70. Here is a link describing the "Oh My God Road": http://www.dangerousroads.org/north-america/usa/728-oh-my-god-road-usa.html
***Note: recommended before beers only.***
http://www.colorado.gov/dpa/doit/archives/cap/first.htm https://www.denverlibrary.org/ http://www.thepeclodo.com/ http://eltacodemexicodenver.com/ http://www.hermanshideaway.com/ http://www.westword.com/location/my-brothers-bar-5160990 http://www.cherrycricket.com/ http://16thstreetmalldenver.com/