- Pycco[1] Python
- Rocco[2] Ruby
- Shocco[3] POSIX Shell
- Many more, as found here[4]
Note each of these projects support highlighting different languages. For example, the Pycco[1] project uses the Pygments library for language handling, and thus supports many different languages. Others, like Shocco[3] only support one language (Shell in the case of Shocco).
[0] - http://jashkenas.github.io/docco/
[1] - https://github.com/fitzgen/pycco
[2] - http://rtomayko.github.io/rocco/rocco.html