If you live in Boulder and work in Denver or vice versa and like to ride bikes then you should consider commuting. I did this route for two years pretty much every day in all conditions and it is pretty good - best done early in the morning.
Here is a link to a post on my old blog w/ directions and map. I wrote an app for my phone to track GPS waypoints along the way so the detail should be good.
http://www.standingmobile.com/bike-ride-from-boulder-to-denver/
Enjoy!
