First call from this number.  When I answered and said hello, there was a pause and an electronic bleep (probably the autodialer switching to an operator after getting a response).  Then a woman said 'hello' and disconnected before I could say hello again. There were 'call center' type noises in the background.  I did not get a chance to find out who it is, but it was clearly a robo-call boiler room.

I didn't pick up (I don't know anyone called "Unknown," you see) and Mr./Ms. Unknown didn't deign to leave a message. Oh well. I shall try to cope with the disappointment.

Had caller ID from day before, but was home and did not hear the phone ring.  Called today, knew my name, lady represented herself as some sort of trade coalition discussing support or non-support of bill before congress.  There was loud sweatshop callbank sounds in background.  Politely cut her off before she got to anything with a hook, not sure what the real objective was.

This time CID said "Richmond VA," where a colleague lives, so, like a big dummy, I picked up. There was a muffled squeak and after a few seconds the line disconnected.

Called me today around noon.  CallerID said UNKNOWN NAME.  Answered the phone and said Hello.  The usual long telemarketer pause, and then I can hear the usual boiler room sounds.  Hello?  No answer.  I said Goodbye and hung up.