Make sure you have epel Yum repo installed, if you don't:

$ sudo rpm -Uvh

Please note that the above instructions are for a 64-bit architecture, on a 32-bit architecture:

$ sudo rpm -Uvh

Make sure you have working version of JDK 6 (including the compiler), if not install it by running:

$ sudo yum install java-1.6.0-openjdk-devel

Proceed with the installation of leiningen "a build tool for Clojure designed to not set your hair on fire":

$ sudo yum install readline rlwrap
$ cd /usr/local/bin
$ sudo wget --no-check-certificate
$ sudo chmod 775 lein
$ lein

First run of "lein" will download all the required stuff and display help, after which you can run interactive shell with simply:

$ lein repl