Fist grab events with “xev” then press any wierd key

for instance pressing my Windows key output :

$ xev
KeyRelease event, serial 27, synthetic NO, window 0x2600001,
  root 0x40, subw 0x0, time 12826166, (175,-6), root:(878,16),
  state 0x20, keycode 115 (keysym 0xffeb, Super_L), same_screen YES,
  XLookupString gives 0 bytes:  ""

the keycode is 115, let assign it with xmodmap (line keycode 115 = Super_L Super_R)

$ $EDITOR ~/.Xmodmap
===# file://~/.Xmodmap===
===# Amilo A keyboard French (azerty) @ http://rzr.online.fr/q/Keyboard===
===# @author: www.Philippe.COVAL.free.fr===

keycode  94 = less greater bar brokenbar bar brokenbar
keycode  22 = BackSpace
keycode 107 = Delete
keycode  49 = twosuperior asciitilde notsign notsign notsign notsign
keycode  59 = semicolon period

===# xev show multimedia keys code :===
===# magic=178 & 236 # win=115 menu=117 # print=110 brk=111===
keycode 178 = XF86AudioLowerVolume XF86AudioPrev XF86AudioPlay XF86Back  XF86WWW XF86OpenURL XF86ApplicationLeft
keycode 236 = XF86AudioRaiseVolume XF86AudioNext XF86AudioStop XF86Forward XF86Mail XF86Messenger XF86ApplicationRight

=== keycode 117 = F14===
=== keycode 115 = Meta_R===
keycode 115 = Super_L Super_R
keycode 117 = Menu
add mod3    = Super_L

===#keysym comma = comma question===
===#keysym period = semicolon period===

===# xmodmap ~/.Xmodmap # xev # cat /usr/X11R6/lib/X11/XKeysymDB===
===# EOF # file://~/.Xmodmap===

Note that we set Super_L as a modifier, like shift, ctrl keys then reload table

$ xmodmap  ~/.Xmodmap

xmodmap -e "clear mod4" # help to use win kde as a modifier on [[KDE]] .

• http://en.wikipedia.org/wiki/Table_of_keyboard_shortcuts
• http://en.wikipedia.org/wiki/Windows_key

@TaG: KeyBoard XWindow