What will be closed or affected by the projected shutdown?
The Smithsonian will be open through January 1 (and the National Zoo) because they have reserve funds.
Yellowstone National Park announced that all lodges and roads would be open. Only visitor’s centers closed.
Anyone else have specific information?
My S said it is rather patchy—those whose budgets were approved (like Dept of Defense) will be largely unffected. He said he believes many of the attractions will be open but no funding for passed for park rangers (different part of budget). He didn’t have much detail as he left DC to come visit us at home. 
Perhaps these lists may be helpful:
http://www.crfb.org/papers/qa-everything-you-should-know-about-government-shutdowns
https://www.whitehouse.gov/omb/information-for-agencies/agency-contingency-plans/
On the wedding thread, a family is having a wedding at one of the National Monuments I think on January 2. They received notification that if there is a government shutdown, the Monument might be closed. But it’s not certain…yet.
What are they supposed to do 10 days or less before a wedding!
https://www.usatoday.com/story/news/politics/2018/12/19/government-shutdown-what-and-wont-close/2349369002/ suggests that about 420,000 government workers providing essential services (including law enforcement and TSA) will work but not be paid until the shutdown ends, and another 380,000 government workers will be furloughed.
Obviously, this can affect the availability of services to the general public that would otherwise provided by the furloughed workers. (Will anyone answer the phone at the SSA or IRS if you have questions?)
Today a woman from Social Security called for a routine review of my disabled son’s information. I asked if she would be affected by the shutdown and she said no, because the budget that was passed last year means that the employees can continue to work. I’m not sure if this is just a specific branch of SS or the entire agency.
NPPD which is a part of DHS is responsible for cyber security for much of our infrastructure is considered non-essential and will be furloughed. The Christmas/New year period is particularly high risk for attack so if action is taken against our public utilities (water systems, electric grid), we will just have to live with it.
I heard that national parks will be open but bathrooms in them won’t be.
Grand Canyon said it would be fully open. In other parks, pit toilets will be open. Lodges are run by concessionaires and will be open.
I doubt barricades will be put up on the national mall as in the past.
The House has left for the night, so at least a partial shutdown is happening. DH is still at work, with a hard stop at 11:59 pm. He’s an essential EE, so could be called in, but only for those issues under that mandate.
The office we deal with is raking big (big!!!) money in, so they were allowed to have some funding stashed away to keep them in business for a few weeks… but I have a feeling that if the standoff continues, the mood there will not be exactly joyful.
The govt shutsdown every day at 5pm est.
Yet the sun still comes up in the morning.
Non-essential? That’s crazy. 
Some parts do; others don’t. Your point isn’t one.
If you live paycheck to paycheck, and are suddenly on unpaid furlough, it’s no joke.
Agencies that have their own budgets outside the general budget continue on. Post Office, military, most agencies like the FBI, the White House employees all continue to work (and be paid).
In the past when the government closed, checks continued. The dept of agriculture handles the payrolls for about 1/3 of government employees, and while my quasi independent agency didn’t close (we had our own funding and budget), we still got our checks from the dept of agriculture.
I don’t know if employees were already given Monday off. Usually on the day before a holiday employees are ‘released’ early, but the last time Christmas was a Tuesday, everyone got Monday off too.
Yes, there was an announcement earlier this week that fed EEs would be off on 12/24.
DH got home from work at 11:30 tonight. It was 10:30 the previous night. Just another day in federal Paradise!
Hugs, @CountingDown.
Once I was working on a merger project and we were scheduled to run the processes to merge some computer systems on a specific 3 day weekend right after the acquisition close was supposed to happen. A federal govt shutdown delayed regulatory paperwork needed for the closing, the sale didn’t close on the expected date, and we had to change the schedule to several weeks later to find a big enough time window to execute it. Cost our client several hundred thousand dollars. Post #11 is ignorant and incorrect. The impacts are real.