rav1e now has automatic Windows builds via Appveyor. To get the latest build, go to this page:
https://ci.appveyor.com/project/tdaede/rav1e/history
Click the latest build labeled with "master", then click Artifacts to download the executable. I'll wire up a better interface for some at this point.
Keep in mind that rav1e is still incomplete, lacking features such as motion compensation, so you should not expect good compression performance. However, it is much faster than libaom and is useful for generating long AV1 test sequences.