We just pushed a Vagrant box config to the GitHub repo for the sample apps (https://git.io/vaw1U). This sandbox is the simplest way to get started with YDK-Py. It provides an Ubuntu (14.04) VM with YDK-Py pre-installed. The "samples" and "projects" directories are shared between the host and the Vagrant box. Any changes to those directories are seen in both environments. Any other data in the Vagrant box is isolated from the host and will be lost if the Vagrant box is destroyed. For now, you need an IOS XR device (6.0.0 preferable, 5.3.0 with caveats). Planning to improve soon. Remember this is the first public release of YDK, so expect changes and many enhancements.
Take it for a spin and let us know what you think!