Replicant isn't nearly as popular as Android itself (obviously) or CyanogenMod, but the FSF believes in it since it tries to be fully open-source. At the moment this Android distribution is running on ten known devices as of its 4.0 release. Among the working devices are the Samsung Galaxy S and Samsung Galaxy Tab.
The Free Software Foundation is trying to raise funds so that it can buy more mobile hardware for the Replicant developers. While I wouldn't expect any really ground-breaking and original innovations out of this free Android project, those wishing to learn more can visit FSF.org. The foundation is also continuing to push its high priority projects.
Details on the upstream Replicant open-source mobile operating system project can be found at Replicant.us.