Received a call from this number at 7:15 CST. Being a CA number that would be 5:15 PST.

The recording says that "this is the IRS and you must return this call".

As lazy as the IRS is - I doubt anyone is at work at 5AM.

Same as above-no it is false just got my return-no problems IRS-some kind of scam-it would have been 7am in CA pretty sure IRS isn't at work or located in CA

My Mom (senior citizen) got an IRS call from same number.
Someone is trying to extract personal information.

There is a widespread IRS or "tax scam" being  practiced by scammers on both Canadian and USA residents.
USA tax payers should read this:
http://www.irs.gov/uac/Newsroom/IRS-Reiterate ... -Telephone-Scam

Short answer:
The IRS never initiates a contact via phone.
They always send a snailmail first.

Educational post:
This scam is also described as scam #11, here:
http://phonehelp.2truth.com/facts.html

If you were contacted by an IRS impostor, you may file a report, after clicking on this link:
http://www.treasury.gov/tigta/contact_report_scam.shtml

Call from this number claiming to be a Julie Smith from IRS threatening to take action against me if I did not call back within seconds of receiving this call.