Caller ID said number was 509-790-0539 from Washington DC, I let it go to voice mail.  Automated message saying the IRS was initiating a lawsuit.  Googled the phone number and saw all these same claims...

Go here and report these idiots. http://www.consumer.ftc.gov/blog/irs-calling
Who knows, it might help stop them.

My brother received a call from 509-790-0539 Sunnyside Washington.  Did not answer it but let it go to the answering machine.  The message was that the IRS was filing a lawsuit against him.  My brother has a traumatic brain injury and requires 24 hour care.  He heard the message and got really agitated and it took me a really long time to reassure him that this call was from scammers and that he was fine.
Can't somebody stop this bottom feeders!!

Same experience with this number- I received 2 calls, both times they left the same message- I called back blocking my number and it did not ring it went to a scrambled busy signal- (my guess is if they do not get a caller ID number it will not go through) There is no way possible IRS would be looking for me, but I would like to find a way to stop all this scam calls-

A call blocker may be a place to start, or if you'd rather not spend any money, blocking unknown numbers or shutting down answering devices and letting the phone ring is free. They can't afford to keep calling numbers that have no answers for long since no profit is made off blanks.