I recently purchased a Samsung Chromebook 3 so I could work on projects during my long commute or at my local coffee shop without worrying about losing or breaking my other more expensive portable machine. It's really nice and light, and with a little configuration, makes for a great portable web development environemnt. After all, ChromeOS is itself a linux distro, but things are a little hidden in this environment as ChromeOS is meant to be easily accessible and to leave the user as little room as possible to screw things up.
Enabling developer mode is very easy and necessary to get things started. This will allow you to access ChromeOS's native shell, or "Crosh", which runs in Chrome as an extension which is really cool; ctrl+alt+t will bring you there. From Crosh, we can then access our typical unix shell by simply typing "shell."
But now lets say we want another distro to run along side ChromeOS?
A chroot, or change root, gives us the ability to run this second distro, without partitioning the disk or using a virtual machine, while still being able to access the same files across both environments. I installed LXDE because the Chromebook I purchased had only 2 gigs of RAM, and used Crouton to create the chroot.
This second distro is nice because if you are familiar with the Linux environment, you can proceed to work as you normally would, with Aptitude, Python, PHP and everyhing else already installed, and without all the limitations of ChromeOS.