Zeta Desktop Environment (ZDE) is an X11 window manager and tools with enhanced usability and features for advanced users and developers. Some of its current sub-projects include imp, a library of core functions such as linked lists, zwl, a simple widget toolkit and light X11 wrapper, and zimwm, the window manager.
Notion is a tiling tabbed window manager for X. This means the screen can be freely divided into tiles that contain the client windows. Multiple client windows can occupy the same tile; in that case they will be tabbed, much like browser tabs. This way, windows will not overlap and it becomes easier to manage your screen real estate. Its functionality can be configured and even extended with Lua scripts. Various scripts are available, such as for NetWM features and multihead support.
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.
DSWM (Deep Space Window Manager) is a tiling keyboard-driven X11 window manager. It is based on StumpWM code and is written entirely in Common Lisp and oriented for good usability with minimum startup configuration and good integration with Emacs. The project is under hard development, so it has many experimental features.