In Sinatra or Flask, you get a server (interface), a routing syntax, and built-in templating.

In Clojure, you have Compojure, which handles routing, Ring, a server abstraction for requests, and responses, and the templating library of your choice. (I've used Hiccup and Enlive, as well as Mustache and Markdown). You're responsible for gluing them together, which is really not too hard given the power of the language to create abstractions on the fly. This results in slightly more code, but also makes it much easier to replace or augment any one component.