"Final Notice" that IRS is about to bring lawsuit.  Leaving threatening message and demands you call back.  Does not use call recipients name in call and does not clearly say that it is IRS calling (but implies that fact.  Obviously a scam.

Fake IRS call.

Received a message stating from IRS, it is a scam!

Just received the same phone call.  I called them back.  They ask for your phone number, then your name, then your zip.  I cut them off at my zip and told them they are the ones trying to reach me so they should have this information.  The guy sounded agitated and said how can I help you if you won't give me the information then hung up on me.  Also, was from an India call center.  Must be some type of scam.  Do not give out any information...and frankly, I wouldn't return the call if you see a missed call from this number.