The car trip via I 70 through Glenwood Canyon is awesome also.
Wanna take a train trip? I give you Durango to Silverton on the narrow gauge steam engine train. WOW.
That trip will curl your hair.
http://www.youtube.com/watch?v=ZdyMOt68MxY&feature=related
I did both of those in 2011 on a trip to California. The drive across Nevada is also awesome. If you have the guts and iron butt for it, the best way to make the Denver to CA trip is on a touring motorcycle.
We took a day trip to Silverton last year two days before Christmas. Such a wonderful place. Local church goers formed a musical band on the street playing Christmas carols and choir from one of the churches singing. Santa arrived on an old timey fire engine pulling a sleigh full of gifts for the kids and fruit baskets for the oldsters. Just lots and lots and lots of snow. In the midst of it all it started snowing again. Just like being at the North Pole. A slice of Heaven.
Great restaurant there called the Pickle Barrel. Wonderful food. Best day trip in a whole lot of years.
The I-70 through Glenwood Canyon is my favorite drive to date.