Whether you are from here or just visiting, there is so much to do year-round in Colorado! We are still exploring and finding our way around but here are some of our favorites.
Sunflower farm – http://www.sunflowerfarminfo.com/ Very fun little play farm for kids. Not sure of their winter hours though.
– Hammond’s candy factory tour (free!) http://www.hammondscandies.com
– zoo and science museum are excellent
– the US mint is here- I think you try to get tickets the morning of. Not quite as fun for little ones though.
– Red rocks is fun to visit during the day and dinosaur ridge is nearby and fun.
-pearl Street is always fun to walk around and eat and shop.
– Nederland is a beautiful drive about 35 minutes from Boulder and a cute little town with a reservoir to wade in and a fun carousel
– celestial seasonings tea factory (free!) (kids have to be 5 & up for the tour but there is a great gift shop and a cafe too.
– CU has a beautiful campus and a planetarium and science museum
– YMCA of the Rockies has lots of fun activities
– Rocky Mountain national park- we love bear lake, alluvial fan, and Alberta falls trails. There is also a sledding hill here: http://rockymountainnationalpark.com/things-do/winter/tubing-sledding
– Garden of the gods (this is driveable if the weather isn’t great)
-Cheyenne mountain zoo
– focus on the family headquarters (free!) and has an indoor playground
– cave of the winds
– pikes peak and manitou springs (you can drive up or take the cog railway, weather dependent)
These articles mention lots of these same things and have web links too.