CID showed Unknown, so I let the answering machine take it. They didn't actually leave a message, but stayed on the line, so the machine recorded boilerroom/call center back ground noise. Scammers.
Unknown Name on CID, so I let it go to the answering machine, and no message left of course. I never answer unknown calls, or pretty much any calls from outside our local numbers. If they are a valid caller, then they'll leave a message on the machine.