This morning's outage, maybe 15 minutes in length, came to us courtesy of the RIPE network in Amsterdam. The specific URL requests seemed somewhat ordinary, but there were numerous attempts to post replies (they weren't logged in). The requests were sufficiently voluminous to require automation and constitute a DOS attack. The IP was 22.214.171.124 if someone's curious enough to investigate further.
Checking the logs, you were accessing the site until 1:40:01 AM, and then not again until 2:06:11 AM, but there were a few hundred accesses from other IP addresses during that period. I don't have an explanation, but I don't think the problem was related to the website. Let me know if it happens again.