Google has pushed out a new build of Android Lollipop to the Android Open Source Project. Android 5.0.1 release 1 is now showing up on AOSP with a build number LRX22C. We'll need some time to look and see what's changed in Google's Lollipop recipe, naturally, but the small version bump isn't likely to change anything monumental. Helping us see what's new are complete factory images, which have arrived for a few Nexus devices.
Google has published factory images for the Nexus 9 (Wifi), Nexus 7 2013 (Wifi) and Nexus 10. You can grab the factory images from Google, and if you need help using those images you can check out our comprehensive update guide.