Switching keyboard layout in X11

There are three keyboard layouts that are in use on my computers:
1. Most time I need the German keyboard layout, because German is my native language.
2. Once in a while I like to use the English one because some characters like '[', '{' (which are used often in programming) and so on are easier to access.
3. Sometimes I need the Russian keyboard layout because I learn Russian and need to write texts in Russian.

In XFCE, it is possible to set up keyboard layouts and switch between them by clicking the corresponding entry in the settings dialog, but if you have to switch very frequently, that is quite annoying. In Windows, there is a keyboard shortcut for switching and also in Gnome it is possible to set that up. However, in XFCE there is only a setting for switching the input method, but none for switching the keyboard layout (at least in version 4.10 that I use in Xubuntu 12.10). But finally I found a solution, that is really simple:

As root, create a file named 65Xkbmap in /etc/X11/Xsession.d with the following contents:

setxkbmap -option grp:alt_shift_toggle,grp_led:scroll at,gb,ru

This would allow switching the keyboard layouts at (German), gb (English) and ru (Russian) by pressing "alt" and "shift" (left or right one - doesn't matter). To see which keyboard layout is currently active, a plug-in can be added to the XFCE panel.