I installed the nvidia driver (installed the ubuntu-x-swat ones, updated them, got the updates for them, installed bumblebee. I restarted everytime I did those steps, so no, i don't simply need to 'restart X'. I tried to run things using bumblebee, but bumblebee was like "can't access GPU driver". So I ran nvidia-settings, it said the drivers weren't in use, so I ran "sudo nvidia-xconfig", then restarted.
Now, my login screen looks differently than it did before: it asks me if I want to load: "GNOME, GNOME - no effects, Cairo Dock - GNOME, System Default, or Ubuntu" when I log in,
but WORST OF ALL: i no longer have any kind of GNOME/unity GUI. There are no title bars above any windows, no close/minimize/maximize buttons. The unity bar is gone, and will not show up when I call it. And the top status bar is also no longer there.
UPDATE: I ended up reinstalling Ubuntu, and doing the following:
1) Installed the linux sources and headers. (These are required to build the driver)
sudo apt-get install linux-source linux-headers-3.5.0-17-generic
2) Add a PPA containing recent drivers: (How recent are these?)
sudo add-apt-repository ppa:ubuntu-x-swat/x-updates
3) Add the Stable Bumblebee Releases PPA and install Bumblebee using the proprietary NVIDIA driver:
sudo add-apt-repository ppa:bumblebee/stable sudo apt-get update sudo apt-get install bumblebee bumblebee-nvidia linux-headers-generic
And now things work. My graphics card is by default off. If I run glxspheres I get ~50fps, and if I optirun glxspheres I get ~150 fps. When I run nvidia-settings or optirun nvidia-settings, I get this: