CL-Ajax (http://cliki.net/cl-ajax) directs JavaScript calls directly into server-side Lisp functions.
The export function script is as follows:
(export-function #'my-function)
Generates a JavaScript stub with arguments.
Can callback to a JavaScript function or DOM object.
May be integrated into SAJAX.
Open source license (custom, very flexible, license) by Richard Newman (http://www.holygoat.co.uk/).