The wiki has been really slow all day. The Apache server and the Squids appear quite happy with life - but the load balancer is reporting huge traffic spikes. More information as I have it.
(The blogs are unaffected, as they're served directly from the Apache server.)
Update: Here's the load balancer connections per second. (The gaps are when logging is killed to increase throughput or something.) Note the bit where we go from a few tens of queries a second up to 800 a second.