Thanks y'all!
Technical explanation:
Early this morning, while the system was getting backed up, the server reported a bunch of disk errors. For safety purposes, it put itself into a "read only" state.
You might recall that the Cellar itself is on a different server than its database. This is why the forum's messaging system continued to work; new posts could be saved, because they weren't not being saved to the read-only cellar.org, they were being saved to the database server.
And that's why I could restore the forum pretty quickly. I just moved the code to another server, and told the Internet that cellar.org should point to that server instead of the old one. The massive database didn't need to move... just the Cellar code that points to it.
Tip Mug considerations:
The server that the Cellar is now on was never meant to manage the Cellar. This server is ancient, in Internet terms. It has almost no memory (256MB, yes MB), and it may slow down terribly once all the users and search engine spiders find it.
What I notice is that there are many fine rackmount servers on the eBay right now. Unless I'm mistaken, many of them seem to be going for well under their actual value. I think this is part of a trend away from running such servers, but it might do us a real solid favor and give us a new home for cellar.org.
SO: any mug donations that happen through Friday will go into the eBay New Used Server fund, and if there are enough of them I'll try to buy two to also replace the current database server. That will make things really speedy.