Under Linux, I use Xmodmap to change the mapping of certain useless keys on my keyboard, such as the Microsoft keys:

File: ~/.Xmodmap

! lines starting with an exclamation are comments
! left microsoft key (between left CTRL and Alt keys)
keycode 133 = guillemotleft guillemotright

! right microsoft key  (U2022 = "big dot")
keycode 135 = degree U2022

! right microsoft menu key (big checkmark, star)
keycode 134 = U2714 U2605

The second mapping is for "shift + key". You can use "xev" to discover keycodes.