1st call- caller was a man with a nigerian accent (or some african country), saying that I owed the IRS money, and that they'd issue a warrant for my arrest unless I made immediate payment. When i mentioned "The IRS doesn't make phone calls, they send letters", the guy got extremely belligerent with me and said that I needed to pay NOW, unless I wanted to go to jail. I simply hung up. 2nd-call: caller was a woman with an indian accent, saying the same things the male caller said, but with the added twist that someone from the IRS Investigations Unit would be coming by my house this evening to serve the warrant. COMPLETE SCAM.
Got a phone call saying they were calling from the Criminal Investigative Unit of the IRS. They threaten that I was under Criminal Investigation and that a Warrant would be issued for my arrest if I didn't call back within a couple of hours.