ABAP documentation
There is a simple tool that automates your ABAP documentation,
keeping it up-to-date with your version of the program.
The documentation is in-code and can be accessed directly from ABAP Workbench.
It interacts the ABAP Dictionary with the code comments, resulting in an interface description of a method or a function module along with the comments.
So the information it generates holds rather a business-value (why stuff happen), than just documenting the code, and therefore can be also useful for project proposals, etc.
You can find it here, if interested.
How often do you generally have to look into/re-pair an ABAP code with the documentation?