Hello!
I've just finished a substantial project in which I tried lots of new Lisp things (for me, that is): foreign libraries, GUI, serial port programming, process spawning etc. It's a real time scientific data visualisation program, and I am pleased to say that Lisp version is faster than C++ one. Attached is the patch (result of darcs send -o) with modifications that I made to cl-opengl in the process. It includes Charlie MacMackin's vertex array patch.
Hope it will be useful.
Sincerely yours, Dmitri