My CID says it is from the DFA. I believe, but cannot be absolutely certain, that this is Democracy For America, Howard Dean's political organization. I never pick up and they never leave a message, so we may never know for sure.
I don't know who is calling , because no voicemail message is left. I do not answer calls that are not identified and do not want to be harrassed by these repeated calls.
I finally picked up and requested that they take my name off the list and they said they would. I would suggest picking up and telling them to take your number off because if you don't they won't stop calling.
My cell phone has a "reject list" feature. I add numbers like this to it and never again does the number ring on my phone! At least until I change phones and have to build up the list again. (Phone is a Samsung Galaxy: I click on the number from my call log, it appears with contact info, I click the bottom left menu button on the phone and that gives me the option to add the number to the reject list).