cl-gtk
Gilbert Baumann's GTK bindings for Common Lisp (for CMUCL, CLISP and Allegro CL). Like CLM, it talks down a pipe or socket to a server process, avoiding icky foreign function call issues.

Tim Daly, Jr. is working on a version supporting GTK+2. http://tenkan.org/clgtk/index.html (previously found at http://www.stud.uni-karlsruhe.de/~unk6/).

October 22, 2004: Version 0.3 Beta has been released.

Feb 8, 2003: Version 0.2 Beta has been released. Be sure to yell at Tim and tell him why it doesn't work for you. :)