If you own an Android device and want to sample Android 6.0 'Marshmallow', but aren't quite ready to flash your device with an entirely different ROM, you might be interested in Android M's 'Google Now' Launcher that is available for download.
While this isn't an official release and it won't give you the full Android Marshmallow experience, it does offer a tiny sample of Google's latest without much risk. The unofficial APK offers a variety of new wallpapers from the developer preview and also performance enhancements. Unfortunately, that's pretty much where the experience ends at it does not offer much more in terms of new functionality.
For those interested and wanting more, Google has released the third and final developer preview for Android M that is currently only available for the Nexus 5, Nexus 6, Nexus 9 & Nexus Player. Be sure to take a look at our hands on of the 'Android M Developer Preview'.
Google is expected to premier the final version of Android Marshmallow with its new line of Nexus devices sometime later this year. It is rumored that Google is preparing two devices, one produced by Huawei and another by LG.