My team at iPlant Collaborative has been working over the past six months on building a solution for crowdsourcing CI development. Within three months, the latest version of this solution will be ready to deploy. What this means is that community contributors will be able to add functional capabilities to the "single cyberinfrastructure for plant biological sciences" without writing code. This feature can be likened to the FaceBook API for adding apps, except that there is no code to write...not even a user interface. Community tools become a part of the CI when an author, or avid user, describes the tool using the tool editor under development now. That description is used to generate both the interface for usage and also the elements required for execution of the tool.
This solution drew heavily upon my experience creating metadata models for systems. The current production system is using the first version of that model now to execute tools that have been manually described. The next release will provide capabilities that allow these community tools to be added more dynamically and by a diverse community. The model also supports user's ability to customize the tool experience and to link tools into pipeline solutions, again, without writing code.