Keep in mind that it's not between 10pm and 1am for the entire world. Some parts of the world were already getting up for work on monday, or part way through their day.
It's not necessarily your traditional "web traffic" causing the grief. It can be a denial of service attack against the server, or it can be what we call "rogue" processes. (That's a program that was running properly, then forgot it's manners and began causing havoc on the computer, by using all of it's resources and such.) It could be that the database is "upset", because of corruption. It could be that there's something broken in phpBB right now.
This problem is actually 99% of the time completely a software problem. Either the database software, the operating system, or the bulletin board software ( i.e. a configuration problem)
The problem is that the people that need to know about it so they can fix it, aren't finding out. I suspect that even if Pete knows about it at this point, that he will still have to be in contact with the company hosting the website. They are the ones that will have to fix the communication problems between the two parts of the server that are malfunctioning.