ShirusuPad is a tiny and very handy tool that allows you to quickly open a topmost note window via hotkey. The window is resizeable and you can copy tons of text into it, for example source code. It saves you the hassle of creating a temporary text file.
On Windows XP it is also possible to make the window transparent. I don’t know why ShirusuPad is still a beta since years now. Maybe the author has stopped working on it. Anyway it already does a good job and I never noticed any bugs except that the transparency does not work on Vista and Windows 7. Thanks to an old colleague who gave me the hint with ShirusuPad.