Perl isn't normally the first language you'd think to use for rendering realtime graphics, but it's quite doable on todays's hardware, and is even pretty efficient when combined with OpenGL display lists and XS (C code linked into perl).
First off, I should mention that I'm not using all the modern fancy shaders or buffer objects that OpenGL offers, and just using the original matrix stack and point plotting. While these might be considered slow for video games with polygon counts in the thousands, it's perfectly fine for polygon counts in the hundreds, and shaders would be overkill. It works especially well with the Display List feature, where you plot the vertices of a model once, then replay the model each frame using a single command. This is also particularly convenient when prototyping; just hack around plotting vertices until you get what you want, then add some display list curly braces around as much as you can pre-compile for a nice speed boost.
Todo: describe X11::Xlib and X11::GLX
Todo: code examples