They did not leave message.
I am registered on the DNC List.
 Jun 10th, 2013
Caller ID says UNKNOWN NAME, left no message. Get a real job. My call was at2:57pm on June 6th. Also on the useless DNC list.
New York
 Jun 06th, 2013
Read the "Annoyed in NYC" comment. Identical situation here. My call came in 06/06/13 @ 2:24pm
New York
 Jun 06th, 2013
I got a call from this number 650-644-4123 on 6/1/13 at 5:17pm at my home in NYC.
My caller ID said UNKNOWN NAME.
I called back the number and heard a strange "ding" and then got a very odd, automated recording of a person which tried to act as if it was not an automated recording. I know that sounds weird but it is the truth. The system was listening to questions I would ask, for key words and then respond as if it was a real person.
The "caller" identified themselves as Jeff Stewart of the American Veterans Support Foundation. When I asked what that was the automated response said it was a "very special project" of the National Vietnam Veterans Foundation. When I asked where they were located they said Eden, NJ (which is odd since the area code is in Palo Alto, CA). When I asked how can I get back in touch with them, they gave me an 800# (1-800-270-0018) which led back to a "Fundraising Company", the woman would not give me her name or the name of the company and she said they were a company which does fundraising for many different groups. I then researched the "American Veterans Support Foundation" and found this posting about them:

"It turns out that they are a legal organization, but although they comply with the law by reporting to the state, in fact they are in business for themselves. According to the attorney general's office, they collected $4.3 million dollars last year. They claim 86 percent for expenses and only 14 percent goes toward helping veterans."
New York
 Jun 01st, 2013
Called 2.23pm Jun 1st 2013. No answer. I am on the do not call list for what it's worth
New York
 Jun 01st, 2013
Unidentified caller who left no message at 8:28 PM. We are on "Do not call list".
North Carolina
 May 29th, 2013