Found an old but interesting and well written article about the k programming language over at kuro5hin. It's a descendant from APL that I have the unpleasant experience to work with. k looks a lot more sane though, using normal ascii-characters and having some more advanced features than APL.
Still, no one can say that k is an easy language to read. Just take a look at this example from the company that owns k. It's an xhtml-parser, basically full of lines like these:
The APL legacy is clear, readability is totally missing.
But for the right task, I'm sure k is an excellent language. I believe in using the right tool for the job. You don't write an OS in ruby, but I wouldn't suggest writing a web-app in c either. (Just take a look at the Hula project. It's not exactly speeding along, look at Rails instead)
I still recommend reading the well written article on kuro5hin, you might just learn something.