At midnight ET on Tuesday morning, the American federal government shut down operations as a result of the Congressional budget impasse. Currently there's no immediate end in sight, so a mish-mash of government agencies are open and closed. National parks and museums are off, but mail is still being delivered to American households.

On Saturday, Ars took a quick look at which US government agency websites would be going dark during the shutdown. Those included the Federal Trade Commission, the Library of Congress, and the National Park Service sites. They all planned to go dark and have done so.

The federal court system is remaining open, as it has a financial reserve that should last around two weeks. Similarly, the United States Patent and Trademark Office could stay open for approximately four weeks.

However, we have now conducted a more thorough examination of 50-plus different .gov websites. In the chart below, we have highlighted whether they are up or down, and what, if any, notice they are giving to their visitors. We hand-selected the federal agencies from a list posted on usa.gov—which obviously remains up.

What emerges is a rather bizarre picture. Nearly all of the agencies we looked at are up, even those with a message about the shutdown. Very few, in fact, have genuinely closed down entirely. (One DC watcher speculated that this White House memo [PDF] may have something to do with the policy.)

We may update this list as needed, but feel free to add more in the comments.

Down for the count nasa.gov "Due to the lapse in federal government funding, this website is not available. We sincerely regret this inconvenience." loc.gov "Due to the temporary shutdown of the federal government, the Library of Congress is closed to the public and researchers beginning October 1, 2013 until further notice. All public events are cancelled and web sites are inaccessible except the legislative information sites THOMAS.gov and beta.congress.gov." archives.gov "We are unable to blog, post to Facebook, or tweet during the Federal Government shutdown. (This does not apply to the Federal Records Centers.)" ftc.gov "Unfortunately, the Federal Trade Commission is closed due to the government shutdown." nps.gov "Because of the federal government shutdown, all national parks are closed and National Park Service webpages are not operating. For more information, go to www.doi.gov." usda.gov "Due to the lapse in federal government funding, this website is not available. We sincerely regret this inconvenience." census.gov "Due to the lapse in government funding, census.gov sites, services, and all online survey collection requests will be unavailable until further notice." trade.gov "Due to the lapse in government funding, the International Trade Administration website you are trying to reach will be unavailable until appropriations are enacted. We sincerely regret this inconvenience." ssa.gov omsre.gov