What does this do? Good question. What you will end up with is essentially Chrome OS and Ubuntu (with KDE) running side by side.
Hold down ESC + REFRESH + POWER, when it reboots hit CTRL + D, and ENTER to confirm.
(You will have to hit CTRL + D at ever boot when you see the scary dev mode OS screen.)
http://goo.gl/fd3zc (documentation: https://github.com/dnschneid/crouton)
Hit CTRL + ALT + T to open the crosh shell.
Type:
shell
sudo sh -e ~/Downloads/crouton -t core,chrome,touch,cli-extra,[unity|kde|xfce] [-r trusty] [-n $NAME]
Time to go get a Mountain Dew. Drink it slow.
Update: Start with a setres command
setres 1680 1120
See all the resolution options with crouton here: https://github.com/dnschneid/crouton/wiki/Chromebook-Pixel
Open the start menu, search for "DPI" to get the font menu and set the font DPI to 200%.
Right-click on the task bar and click on height to adjust the height.
Open the Window Decorations setting. Click on Configure Decoration, and set the button size to "huge". Fix the stupid thing where KDE doesn't allow you to disable the trackpad tap by installing a special config app...
sudo apt-get install kde-config-touchpad
...then...:
mkdir ~/bin
touch notap.sh
chmod 777 notap.sh
vi notap.sh
...and...
#!/bin/sh
synclient MaxTapTime=0
synclient MaxDoubleTapTime=0
...finally add:
/home/$(`whoami`)/bin/notap.sh
to /etc/rc.local before the "exit 0;" line.
Once installation is complete run the following once:
sudo enter-chroot startkde
...and then enter the following when you want to start Ubuntu (now, and after full machine reboots):
sudo startkde
Otherwise, you can flip to Ubuntu by hitting: CTRL + ALT + FORWARD (arrow) then CTRL + ALT + REFRESH. Flip back to Chrome OS by hitting: CTRL + ALT + BACK (arrow)