In an incredible example of PHP's flexibility, there's this example of what it can do with the properly applied knowledge (and a little patience) - the creation of a 3D raytracer.
I mentioned recently that I was looking for an interesting PHP project. This evening I remembered an idea I had a while ago to make a 3D renderer in PHP (and if anyone's tempted to ask - "because I can" ). I did a bit of reading on old 3D engines, as I didn't want something modern and slow, and found out that the "raycaster" rendering used in Wolfenstein 3D is ridiculously easy to implement.
A few hours later and it's up and running I've not run any proper speed tests yet, but the images load up pretty much instantaneously. I have a couple of ideas of what this could be used for, so watch this space.
Screenshots are included in the post as well as tons of comments from all about the web (it was also linked on digg). He hasn't released the source for it yet, but it'll still be an interesting project to keep an eye on. In the meantime, there's always Kore Nordmann's Image_3D project to look into.