Colorado Springs is the 39th largest city (by population) in the US. If you like the outdoors, there are plenty of hiking trails, golf courses, the Cheyenne Mountain Zoo and Garden of the Gods that you can enjoy. The Manitou Incline has been featured in several health/fitness magazines, but if you haven't trained for it, be careful! It may take an hour for a Search & Rescue crew to get to you if you get injured. The Air Force Academy is on the north side of C. Springs, but you'll have to check and see if they are giving tours as they do have security at the gates, and they may not be allowing visitors at that time.
There are many other attractions like the US Olympic Museum located in Downtown Colorado Springs. The US Olympic Training Center is located in a different part of our city, but they may not be giving tours at that time of year. We also have a new Dave & Buster's, Main Event and RailYard which have arcade games, bowling and laser tag as well as drinks/food. Old Colorado City is located close to the wedding venue as is Manitou Springs. You'll want to check the schedule, but you could drive up to the top of Pikes Peak if it is open at the time of your visit. There is also Cave of the Winds and Seven Falls in the area. Or put on some business casual attire and go walk around the grounds of The Broadmoor, a 5-star/5-diamond resort (unless you are staying there already).
We have many restaurants all over this city as well, from diners to fine dining. Denver is about an hour north of Colorado Springs if there is anything that you would like to see there during your visit. Casa Bonita is open again, but you have to have reservations to get in and the waiting list is still long, so that may not be an option for you. Also, if you decide to go to the Broncos/Raiders game, you will be very late to our wedding, just saying!
Checking out Groupon to see if there are any discounts for the attractions that are listed above is highly recommended.