Press Alt in a ribbon UI, and the UI gives you a stable multi-level hotkey set:
http://imgur.com/ZYaxc,xQiiK,2WbYk,VVW0S - this is when pressing alt, r ("start menu"), au ("auswählen" = select), f ("fangen" = catch - the icon for "select" changes in the last picture).
You can move backward using ESC, too: "alt-r, au, esc, esc, a" puts you in the "Ansicht" (view) ribbon. Once in "alt-mode" it always shows you what you can do, and how.
http://imgur.com/ZYaxc,xQiiK,2WbYk,VVW0S - this is when pressing alt, r ("start menu"), au ("auswählen" = select), f ("fangen" = catch - the icon for "select" changes in the last picture).
You can move backward using ESC, too: "alt-r, au, esc, esc, a" puts you in the "Ansicht" (view) ribbon. Once in "alt-mode" it always shows you what you can do, and how.