According to http://www.android.gs/android-5-0-l-factory-images-for-nexus-5-and-nexus-7-available-tomorrow/
there will be Factory images of a beta release of Android 5.0 for Nexus 5 and 7 tomorrow.
discuss
there will be Factory images of a beta release of Android 5.0 for Nexus 5 and 7 tomorrow.
discuss
According to Google, the factory images are only preview builds and not the final version of the operating system, which means it can come with bugs or unfinished features, in order to allow developers test their apps for it and take advantage of the 5000 new APIs it comes with. Along with this, I believe the company is also expecting testers to report back the bugs they find so they can fix it before the official release to the public.