Blackbox shells allow you to interact with your operating system in much the same way as Windows Explorer. However, Blackbox dispenses with some, or many, of the graphical features which are a staple of the Windows model. For example, you won't find icons in Blackbox menus, nor will you be able to drag menu items to reposition them. Generally speaking, you will find a Blackbox environment appears spartan and minimalistic compared to a normal Windows interface.

Porting Gnome Desktop to Windows, using Cygwin as porting tool and running environment

GeoShell - The premier minimalist Windows shell replacement.

KDE on Cygwin is the port of Qt and KDE to Windows using Cygwin, the POSIX emulation layer for Windows, and the Cygwin XFree86 server.

Litestep is a windows shell replacement licensed under the GPL, for Windows 9x and up.

SharpEnvironment is a shell replacement for Windows that aims to create a more user-personal, beautiful computing experience that is conducive to productivity.

Virtual Dimension : a free, fast, and feature-full virtual desktop manager for Windows platform. The main goal of this open-source project is indeed to enhance the Microsoft "Window Manager" up to the level of usual Unix Window Manager, by providing virtual desktops, as well as some additional features, like always on top, window shading...

xoblite is a shell replacement for Microsoft Windows, based on BB4Win and Blackbox. It has an integrated SystemBar, Slit and other features.

DM2 provides several Windows enhancements that may help in every-day work. One of the nicest and most popular features of DM2 is minimizing windows to floating icons^® (unique feature!) freeing both task bar and tray bar space. Moreover, DM2 can manipulate windows in various ways: minimize to tray, make them standing always on-top over all other windows, roll to caption, resize, align to screen borders, hide, set the opacity etc. DM2 also helps with Open/Save dialog boxes, by providing user-defined menu with favorites and recent files and folders. Plenty of program's settings options will satisfy most of requirements.

LDE(X) is one of the most developed LiteStep-based Windows interface replacements ever. It has been developed to suit the most demanding of workloads within the tightest of deadlines - every tool or application you need is always close at hand. For those needing the ultimate power, the environment is highly flexible and open to third party development in virtually every way.