Quoting Hector Gonzalez (cacho@???):

> You can also do this, assuming your original user is "user":
> XAUTHORITY=~user/.Xauthority
> export XAUTHORITY
> DISPLAY=:0.0
> export DISPLAY
> and use x with that.

Some of us like to do 'ssh -Y root@localhost' because we got tired of
messing around with MIT magic cookies and the DISPLAY variable. ;->