Comment Literate Programing (Score 1) 580
Don Knuth described Literate Programming in which the program is embedded in comments, one using a preprocessor to write the program. The preprocessor runs as a command processor, using the source as a batch file. One gets a properly sorted batch file as output. Because of this, one can overcome limitations of the programming language, use pre-processor variables etc, and produce several linked files etc.
Documentation is relatively straight forward, since one writes what one wants to get, limitations, API and examples by way of a wish-list, and then create the routines that make this happen. You can write a tight section like "File I/O", for fileopen() and fileclose() along with getline(), putline(), etc, without exposing the filenames to all of the subroutines. I've written a program to write Web pages in it, for example, http:\\www.os2fan2.com\pgloss\index.html and its attendent pages. It's pretty elegant really.
The temptation of LP is to use it to solve a problem per source, a note that Jon Bentley (Pearls of Programming) noted. LP is about sorting problems: however, the sort of problems that Knuth sought to solve are complete things in an educational setting, not bits of problems in the real world. None the less, I use it to write terse batch files etc, where the LP source is the help file too.