Don't forget leiningen (it's mentioned on the page), technomancy's sweet looking Clojure build tool. The two really do go hand in hand.

InfoQ has an article about the leiningen / clojars one-two punch:

http://www.infoq.com/news/2009/11/clojars-leiningen-clojure

Good name. I knew exactly what I was going to find at the other end of the link.

The individual jar page should have a link to the git repository, or maybe even to the commit that the jar was built off.

looks like a gemcutter.org clone, for clojure?

That is exactly right:

http://groups.google.com/group/clojure/msg/7477fbf2f855c516

List of all clojars:

http://clojars.org/search?q=org

A killer tool/jar/utility developed in Clojure would help me better understand it's power.

Really needs a browsing feature linked to from the first page