Perl OS is a program that provides an easy interface to run Perl/Tk programs. It was also created to be an easy working environment, complete with a text editor, paint program, and more. It comes with several programs, along with a utility to add many more which can be found on the Internet. From the outside, Perl OS looks like a simple operating system. But inside, it is a powerful system for working with Perl and Tk.
awesome is a highly configurable, next generation framework window manager for X. It is very fast, light, and extensible. It is primarily targeted at the power user, developer, and anyone dealing with everyday computing tasks who wants to have fine-grained control over a graphical environment.
awm is a custom window manager. It's small, functional, and fast. It is based on dwm and is just ~1800 lines of code. It is based on the workspace concept, but the space is two dimensional. Each time you move to a new, unvisited workspace, a terminal window is automatically launched, emulating TTYs' behavior. You can delete an entire workspace, killing all the windows launched in it. You can even delete an entire dimension, deleting all the residing workspaces. To resize a window, you just Alt+RightClick on any point of the screen, and the window will immediately resize. The windows can be ordered on the fly with the tiling algorithm of dwm, and then restored. This is useful to get a quick glimpse of the current workspace. A proc-like interface can be used retrieve information from awm.
iloog is a Gentoo-based live CD targeted mainly at students and scientists. It features UnionFS filesystem support that enables you to write everywhere on the LiveCD and install extra packages, a graphical X environment through the Fluxbox window manager, many programming editors and IDEs, and a plethora of scientific applications, including Octave, Namd, Merlin, and full (La)TeX support.