The Colorado Rockies will be playing at home the week of August 28th. Coors field has a nice rooftop bar situation and you can get game tickets for pretty cheap because the Rockies are terrible.
Meow Wolf is hard to describe. According to them they are "an immersive psychedelic, mind-bending art and an underlying rich narrative as you take a journey of discovery into a surreal, science-fictional epic".
Red Rocks is hosting a variety of artists the week of the wedding including Duran Duran, Young the Giant, and Rezz. You can also go during the day and hike around the area.
Denver is known for craft beer and the people who love to talk about it. Some of the big ones are: Denver Beer Co., Odell's, Left Hand, Breckenridge Brewery and Blue Moon. Some smaller, but still good ( maybe better) are Ratio, Our Mutual Friend, Upslope...