Somewhere between the boards being inaccessable until our tech guy fixed them and the fact that a bunch of files had been screwed up in the database...we realized we had had a hacker.
It wasn't a simple info gathering hack, it was a "screw up the boards" hack. Luckily, either the guy didn't know what he was doing or didn't want to mess stuff up too badly.
Some guy from Phatooine posted at our site saying their forums were hacked too, and all banned members were promoted to admin.