Our front-end cache is able to filter out most low-level attacks. However, the level of traffic (728 MBit/sec, about 2000 times what we typically serve, let alone receive) is such that our hosting provider has removed access to our server to protect its other customers, including timduru's sites.
This attack has not damaged the server or its data, which we have backups of, nor do we believe any user information has been accessed. We are working with our hosting provider to get the server back online as soon as possible.
Update: As of Monday morning, our hosting provider has restored service.