Called from "Energy Conservation Allience", supposedly a non-profit choosing homes in my area for evaluation or survey about energy use (I think). Kid said he was calling from Denver, which is the 303 area code. Caller ID shows a 307 area code so there's an easily verifiable lie right there.
Found a great and condemning page from others who have dealt with these criminals right here:
http://800notes.com/Phone.aspx/1-720-763-3498
Actually they may not be criminals; that takes a conviction in court. Nevertheless, I would not trust these people to shovel my sidewalk.