obscure mac tweaks x11 dashboard etc.

Not for the first time, I'm tweaking my mac.
In the course of doing it I've re-discovered a few tricks.
(Thanks http://tazman.princeton.edu/osx/)

Disable dashboard
defaults write com.apple.dashboard mcx-disabled -boolean YES
killall Dock

for X11
I used RCenvironment from www.rubicode.com/Software/RCEnvironment/
to set DISPLAY to :0.0