wmbday is a small dockapp that reminds you of birthdays. It can take an arbitrary number of birthdays, and will display the next four upcoming birthdays. By left-clicking a name, you can see the remaining days until the birthday. The colours of the background and the font can be customised.
libDockApp is a simple library for easily writing Window Maker dock applications, also known as dockapps (those that only show up in the dock). It is very limited and can only be used for dockapps that open a single appicon for each process in only a single display, but this seems to be enough for most, if not all, dockapps.