Don't call them back!  Never return their calls.  Block them.  This is a total scam being run out of India. Or Pakistan

Of course the government works on weekends!  Some agencies have operations working 24 hours a day, all week!   - law enforcement, orphanages, jails and prisons, hospitals, probation and parole monitoring, road building and maintenance, fire departments, facilities' physical plants, ...  The IRS might not have much going on on the weekend, but 'the government' is working all the time.

We've had 2 calls from this number. We reported to IRS.

I have received two calls from 415-506-2394 on 10/28/2014.   I will block the calls, but am reporting this scam call.

S is the 3rd call i received today.