Broken Glass is an application with scripts that let you build a Live CD version of Windows 7.
Broken Glass uses Windows AIK Legal way to make a Live CD version of Windows 7. Aik was made for programmers who needed to test if there applications would work on Win7, and for making customizable Win7 installs. So basically AIK is the "bare bones" of Windows 7. It has no "Windows Explorer" or start menu.