I've installed GalliumOS on my Acer C720 Chromebook, and I have to say that I am very impressed at how fast it runs. With Chromium, its as functional as a regular Chromebook, with the added benefit of a full Linux distro based on Ubuntu.

Here is a good article that describes the install process. One downside that after the installation all I have is 9 GB of storage space. 

I've installed git and nodejs and successfully tested an installation of River5. I've also installed Sublime, Standard Notes, and Skype beta.