From my web hosting service:
We experienced a major hardware failure that caused several hours of downtime for all hosted sites.
This problem is now resolved, and everything is now returning to normal.
We are very sorry for this problem, which was largely caused by difficulty in getting some of the larger filesystems to check properly when the master fileserver reboots.
We will be changing the filesystem-checking mechanism used, and we have already ordered additional equipment that well help us exert tighter control over circumstances like these, should they arise again in the future. We will also accelerate our plans to develop a second location to provide additional reliability and information during severe outages.
Again, we are very sorry about this problem. We do our best to provide the most reliable possible service at our price point, and problems like these are very frustrating and disappointing for us, doubly so when the situation is so bad that we cannot even keep our members properly informed.
I woke up this morning and my site was down, and man was I cranky! But the problem is resolved now.