Caller ID says "Woodbridge VA". They leave no message.
I call back after hours (using *67 to block my number). Their message is "You've reached campaign headquarters. Press 1 to be placed on our do-not-call list. <pause> Please, leave a message after the tone." Then they hang up. I press nothing as it can actually make things worse.
They fail to identify themselves which is a very bad sign. Being (supposedly) in Virginia is much like being called from D.C.; combining this with "campaign headquarters" tells me this is probably someone soliciting funds for political purposes. I looked elsewhere, but discovered nothing furter about this number.