This project is the Hello World of Clojure.
I like the simplicity of Clojure and the newness of it so I decided to get started learning it on http://www.braveclojure.com/
These are the most important take-aways from my first attempt
The Clojure language is a Lisp dialect with a functional emphasis whose syntax and semantics are independent of any implementation. The compiler is an executable JAR file, clojure.jar, which takes code written in the Clojure language and compiles it to Java Virtual Machine ( JVM) bytecode.
JVM processes execute Java bytecode. Usually, the Java Compiler produces Java bytecode from Java source code. JAR files are collections of Java bytecode. Java programs are usually distributed as JAR files. The Java program clojure.jar reads Clojure source code and produces Java bytecode. That Java bytecode is then executed by the same JVM process already running clojure.jar.
In short: Clojure code is compiled by the Clojure compiler into a Java bytecode. The same way that Java source is compiled into Java bytecode. The JVM runs Java bytecode.