I want to use my right Alt as another Control key to use with Emacs.
I tried following (with modifications) this tutorial: http://earthviaradio.wordpress.com/2012/02/06/swapping-the-left-alt-and-ctrl-keys-in-ubuntu-11-10/
So now I have this in my .Xmodmap file:
clear control
keycode 108 = Control_R
add control = Control_L Control_R
After I restart X.org, it doesn't seem to have an effect on how keys behave. Key 108 still functions as Alt. But when I explore it with xev, I can clearly see my changes. When I press the right Alt, I get this:
keycode 108 (keysym 0xffe4, Control_R)
It seems to "know" about my changes, but to not respect them.