Keyboard:  ESC
Command:  Window.ActivateDocumentWindow
Versions:  2008,2010
Published:  6/1/2010
Code:  vstipEdit0066

This is one I had forgotten about until someone brought it up recently.  Did you know you can get the active document window by just hitting ESC?

For example, if you are in any tool window (like the Output window):

And hit ESC, then it takes you back to the Editor:

You may have to hit ESC multiple times depending on the situation but it should always wind up at the active document.  I haven’t found a place that you can’t use this feature but I’m sure there is one so try it yourself and let me know if you find some place this doesn’t work.