klatschbase
Klatschbase is a web based chat software application by Christian Haselbach using AJAX and a REST like API with polling and JSON as data exchange format. The server side is implemented in common lisp and requires hunchentoot. The client side is implemented in Javascript.

There is also a live version of klatschbase.

ASDF-install package (obsolete) http://mr-co.de/projects/klatschbase/klatschbase-0.7.tar.gz