I wasn't surprised to see PHP do well as having the shortest path to a responsive site (in the most minimal sense) is PHP's greatest feature.

I was working forwards from the Ruby example for all of these, so I may have implemented the Clojure one in a weird way.

PHP cheats a bit to be the shortest, since it just looks up files to execute and renders stdout as the result, removing the need for routing.

Well, that's one of the few "advantages" of PHP.

Though PHP allows this to happen easily, it's a fairly terrible idea for production code - the shortest isn't always the best.

In reality you'd use a macroframework like Symfony or a micro like Ham https://github.com/radiosilence/Ham

There is a microwork made from Symfony components called Silex: http://silex.sensiolabs.org.

Edit: I mis-read; reworded for clarity.