Thanks to it being posted on reddit, the traffic to a certain post on Michael Kimsal's blog gave him a crash (literally?) course in high load management on a WordPress blog.
The blog post was voted up on reddit, and the server got slammed. So slammed, in fact, that it was unusable for a few hours while I investigated the problem. I didn't know the post was on reddit, but I knew I was getting some traffic.
He spent some time trying to get the Apache server to finally die off and give him back his machine, at least enough to get a feel for what was going on. Part of his problem was not having APC installed like he thought and the other part - WordPress. While friendly on the outside, it's apparently somewhat lacking on the inside.