I got a voice. Man, who tried to pronounce my last name. (nobody usually can, but he really butchered it.) I just left it and said yes, and asked who was calling. Got a hangup. Called back and got "the person you are calling is not receiving phonecalls at this time." Given it was a light and cheery voice, i don't think that was the phone company's recording.
The same call just happened to me as TMeg described. I wonder if it is someone hired to verify phone numbers for a company that sells call lists. Rather than explaining, this is probably the easiest method although it seems rude.
Duct cleaning solicit. Just hung up when they asked for Mr or Mrs (my daughters last name) which is not the same as mine.
I'm on DNC, but that's pointless.