The annual holiday levy moratorium by the IRS does end on 12/28. It began on 12/4. If you are in IRS collections or with an IRS Revenue Officer, you should definitely gear up to communicate with IRS or hire Washington Tax Services to represent you.
Holds on collections can be put in place next week. If you have blown off the IRS, be ready to get a levy to your bank account, wages or accounts receivable. Of course - don't completely despair as these levies can be released if you are properly defended.