In the wee hours of the morning, the topics table of the database crashed for some reason. Doesn't look like anything in specific that caused it, but sometimes when you're dealing with huge databases containing hundreds of thousands of rows, things lock up to prevent data loss or something.
Originally I said that I would be rolling back the Forums to last night's backup. It turns out that it wasn't necessary. After a bit of investigation and running some commands to repair the table, it was quite simple and everything seems to be there. No rollback was necessary, though it wouldn't have really gotten rid of that much anyway.
There is a slim chance that I might have missed a topic somewhere and a rollback will be necessary, but I'd say it's closer to like a 0.001% chance in all honesty.
Nothing serious, no show to see, problem resolved, hope you had a nice Sunday off. One week to go until HeartGold and SoulSilver and I am absolutely swamped with work.