SOME OF YOU WANT TO KNOW HOW TO GET CMD ON CHROMEBOOKS
Follow these steps:
Go through the standard Chrome OS login screen (you'll need to setup a network, etc) and get to the web browser. It's OK if you login as guest.
Press [ Ctrl ] [ Alt ] [ T ] to get the crosh shell.
Use the shell command to get the shell prompt. NOTE: even if you set a password for the chrome user, you won't need it here (though you still need it for sudo access)
Shell command in crosh: shell
-Lesson provided by HeroTrickshot