I had a call from this number after 9:00 pm Pacific time. Since I don't know anyone who would use it I didn't answer and the caller did not leave a message.

I had the same experience as @Jeff in MD.  Gave $10 to a door-to-door solicitor last year.  Her issue was clean-up of Potomac.  The daily calls continue.  Thank heavens for Caller ID!

I spoke to a very nice man who claimed that if I coughed up $2000 - that they could solve global warming.  Sounded like a good idea -  so I did send off a check for two grand - and sure enough - it is now getting colder - but that could be because I live in Wisconsin and I could not pay my heating bill this month.

There was a distinct sound that resembled someone hanging up as soon as I answered it. Creepy.

an unsolicited call

Just did the same thing, thanks for the idea. I get tired of hearing from them.

Call from Environment America -

Have asked them to remove me from their list but to no avail.  This is all due to the one time donation I made to them on the street in downtown DC several years ago.  Stupidly, I gave a phone number.  Fortunately it was the land line number which we have used less and less over the years.

Since they wont remove me (for whatever reason) despite my promise to never donate again due to this behavior, I now have the number successfully blocked.