They robocalled me and left a message that they're from the IRS, it was my final notice, and they are filing a lawsuit against me.  I called them back and a person with a heavy accent answered.  I told him that I know this is a scam and that I'm notifying the police.  He responded, "yeah f**k with you".

I reported them to TIGTA here - https://www.treasury.gov/tigta/contact_report_scam.shtml

From the IRS's website
http://www.irs.gov/uac/Newsroom/Phone-Scams-C ... 5-Filing-Season
The IRS does NOT initiate contact via the phone.

If someone calls you claiming to be the IRS, please report them here;
http://www.irs.gov/uac/Report-Phishing

Same call 09/04/2015 @ 9AM. ... This was to Arcadia CA... Always a pain to explain this (cuz I'm a CPA) to my clients. Good luck to the next "looker" at this site!

Same exact scenario here.  Boca Raton, FL

I just called the number back and I couldn't understand what the guy was saying so I asked for someone who spoke English so I could figure out what was going on and the guy told me I couldn't speak with someone else and he hung up on me