You should check out lispbuilder-sdl or RLX. (I'm also working on CL bindings to Ogre but they're not really ready for public consumption.)

lispbuilder-sdl is fairly mature to the point that it even has a user manual

http://code.google.com/p/lispbuilder/wiki/UsingLispbuilderSD...

SVG is XML-based and it's very easy to output graphics from your code from any programming language. There's a cl-svg library (http://code.google.com/p/cl-svg/) but I haven't tried it. There's also cl-cairo2 (http://www.cliki.net/cl-cairo2) which is based on the cairo library.

For realtime 3d graphics there's cl-opengl (http://common-lisp.net/project/cl-opengl/). I'm using it right now with sbcl and the glut wrapper (cl-glut). It comes with some examples too.

If you use an embedded lisp such as ECL or PLT Scheme, you can take advantage of whatever graphics facilities the host offers, and code in lisp with a "live" repl.

This project might get you started:

http://createuniverses.blogspot.com/2009/09/qtimagine-skelet...

Yes- I render out graphics to SVG and graphviz and do stuff to interact with a web browser to display it.