I know this is a little old but it's still cool to do.
How to get Android apps on you're Chromebook
(Step 1: Getting the Official Run-time Beta Extension)
You will need to have the official run-time extension on you're Chromebook in order to run Android apps on the Chrome OS. Easiest way of getting the run-time extension is to download one of the official Android-Chrome apps such as Evernote. Note: Evernote will tack some time to download because it will download the App and the Run-time Extension.
(Step 2: Convert the Android App)
Next, you will need to download the Application twerk tool to convert the android apps you want to use.
I will using the Twitter apk for this.
Type in the info you want to use for the app, when you are down click on the android logo to convert the app
If it goes well you would get this
(Step 3: Installing the App)
In your Chromebook you will need to open up Chrome and go to settings –>More Tools –>Extensions. Make sure developer mode is checked and select load unpacked extension. Navigate to the folder of your application and choose open.
If it goes will you well get this
Next open the app and you will need to wait a little for the app to load
Not all apps will work with this.
Don't know if you guys still use Chromebooks but at Google I/O they mentioned they would somewhat bring the Play Store to Chromebooks so you won't need to go through this complicated process. Now they're crazy useful since you won't need internet to access Microsoft files and all. You'll also finally have VLC and Skype!
Still waiting for Crunchyroll to add new stuff to my region.