There is a kite retailer in Boulder. You might want to check whether they sponser or host any events.
The website for the Foothills Kite Club is here
, but outside of monthly flies, their first event is listed as April 10th.
The Rocky Mountain Kite Association is located in Golden. Their website is here
, but it is a tad disjointed. If you have an account, you might have better luck on their Facebook page
Denver is also the home of One Sky, One World
There are about 40+ AKA kitefliers in CO, you might want to introduce yourself on the AKA public forum
So far there are only 3 CO kite events listed this year:
04/10/2010 8th Annual Arvada Kite Festival at Robby Ferrufino Park, Arvada, CO, USA
05/01/2010 Fort Collins Kites in the Park Spring Canyon Park, Fort Collins, CO, USA
10/10/2010 ONE SKY ONE WORLD Stapleton Central Park, Denver, CO, USA