Now that I am remembering better, I actually hit the front page of Reddit and del.icio.us at the same time. Those both drive a surprising amount of traffic. (The article was "Git merging by example", now archived here: http://blog.jrock.us/posts/Git%20merging%20by%20example.pod)

I did not use varnish at the time, but I basically kept up with the load. My pages were cached with an in-memory cache in the app layer, which worked well enough, I guess. As blog.jrock.us mentions, I was unhappy with the design of my software, so I took it down. Two years later, I almost know what a good design is, and so I should have a blog again soon. But I digress :)

Needs to prove it!