In recent years, many agencies and government authorities have been moving toward opening up their datasets, allowing external parties to create applications that can mash up this data. As the amount and the variety of data is increasing, it is important to create good metadata (descriptions, geographical boundaries, limitations, etc.) in order to allow individuals, who may not be domain experts, to easily search and consume data. In this paper we propose the Open Innovation Portal (OIP), a collaborative platform that allows Cities to annotate, publish and provide access to urban data from multiple sources in an intuitive, consistent and scalable way through open standards. In collaboration with Dublin City authorities and National University of Ireland Maynooth, we implemented a first prototype for Dublin. In the demo, we show how the collaborative metadata creation process works, from the raw data to the publishable information, and how the collaborative platform can be implemented both for a mobile-phone and web application.