Unknown caller.  Left no message called at 7:18PM MST.  Another site confirms this call originates from Breckenridge CO.  Wonder if "Marg" is correct above about call coming from "Timberline Lodge" as I just finished a vacation in CO. No doubt my number was used to confirm bookings and potentially sold to these creeps.

1 call on 9/5/08 and one 9/9/08 both in the evening no message

Strangely enough, two days ago both my wife and I got calls from this same number within minutes of each other, and now today it happened again. It must be a computer dialing and we our numbers are in the same sequence. I wonder who the creep is who sold them our numbers.

Iv'e gotten a few missed calls.  I just called them back and it was Grand Timber Lodge in Breckenridge, marketing department.  I've never stayed there, but it may be connected to places in Keystone, since i have stayed there.  I just left a message to have them remove me from the list.  I'll try to update if I get some response.
http://www.grandtimber.com/

I imagine it may be the same with any cell phone, but I called Verizon and they allow you to block 5 numbers for free.  It may be worth giving your phone service provider a call and just tell them the number.