I heard that Haskell had a "literate programming" form that integrated with LaTeX and decided to try it. The result is a simple computer algebra program. The .tex files can be run through LaTeX to generate the documentation. The .lhs files are simply soft-links to the .tex files. They can be fed into the Haskell interpreter of your choice and are the source code for the program.
It's been a few years since I tinkered with this, but I hope that someone finds it interesting and/or useful. It's a bit more than a few short examples and a bit less than some monstrous application. If you look closely, you can even tell where I stopped.