#apt-get install closure
#closure
user=> (+ 2 2)
4
Most of that 45 s was waiting for apt-get.
Now it's not going to be this easy on platforms that don't have such nice package management (e.g. Windows). Furthermore, Raphael_Amiard makes a good point that there's a lot more infrastructure that has to go into web application development (or any other kind of application development, for that matter) than computing the sum of 2 and 2.
Nonetheless, it just doesn't seem that hard. At worst, put a "clojure /path/to/project.lisp" in rc.local or equivalent.
(Caveat: my web development experience consists entirely of a couple of toy projects I ran on my laptop for my own amusement. Take all this with a grain of salt.)
EDITed for formatting.
I don't know why the Enclojure plugin for Netbeans isn't mentioned more. It provides an interactive development environment for Clojure in package that is much easier to digest for anyone who is familiar with an IDE.