Here is a transcript from a fake IRS call I received:
Hello, this call is actually a final notice from IRS Internal Revenue Service the reason of this call is to inform you that IRS is filing lawsuit against you to get more information about this case File please call immediately on our department number 337 290 0560, I repeat 337 290 0560. Thank you.

fake IRS call I received:
This call is a final notice from IRS Internal Revenue Service the reason of this call is to inform you that IRS is filing lawsuit against you to get more information about this case File please call immediately on our department number 337 290 0560

Definitely a fake "IRS" call.  The fact that it came up on caller ID as a cell phone from Louisiana is a big tip-off.  Here is the message I got:

"Hello this call is officially a final notice from IRS Internal Revenue Service. The reason of this call is to inform you that IRS is filing lawsuit against you to get more information about this case file. Please call immediately on our department number 337-290-0560. I repeat 337-290-0560. Thank you."

I have had several of these calls recently.I had the pleasure (not)last year of actually speaking to one of these morons,who stated with a thick Indian accent that he was officer Michael Brown of the IRS.He stated that if I did not give him 2500 dollars immediately the police would come in the next half hour and take me to jail.
These people are scammers.The real IRS will not do this.These people will stop at nothing,including cursing abuse and threats to get your money.Do not fall for this.Tell them to f*** off and get a life and a proper job.