Vitrite is a tiny utility that allows you to manually adjust the level of transparency for almost any visible window. It works by utilizing a feature present in Windows 2000/XP (and all later incarnations) for variable window transparency.

When executed, Vitrite minimizes to the system tray in the lower right corner of the screen. If you wish to make a window transparent, you simply bring the window into focus (i.e. click on it) and press Ctrl Shift [any number on the top row on the keyboard]. There are 9 different levels of transparency: 1=90% transparency, 9=10% transparency, and everything in between.

Vitrite also has the ability to toggle a window's "always on top" flag. Just press Ctrl Shift + (that's the plus sign) and it will make the active window float on top of the other windows. Press it again to reverse this behavior.