The first is the LiveCycle Productivity Kit which contains a whole bunch of helper classes for working with the various API’s. I’ve seen plenty of examples of these classes being used for integrating Flex & ColdFusion with LiveCycle solutions. One use case is to have a Flex app interact with LiveCycle Workflow to start new processes and query the status. Another is to query the LiveCycle Form Manager repository. This library of classes has been kicking around within Adobe for a couple of years now and its good to see it cleaned up and opened up as an open source project.
RIAForge is definitely worth checking out.