If you want a "fun" physical challenge you can try and completer the Manitou incline! This is the most challenging hike in Manitou Springs. 2744 steps climb 2000 ft. in elevation in under one mile. Plan on 2+ hours for this 4.5 mile round-trip hike.
You can drive or take the cog railway up to the top of pikes peak! The railway is such a fun way to see the whole mountain!
Fort Collins is about an hour from Denver and has lots of different breweries to go and check out and tour!