In a previous paper, we laid out the vision of declarative datadriven coordination (D3C) where users are provided with novel abstractions that enable them to communicate and coordinate through declarative specifications [3]. In this demo, we will show Youtopia, a novel database system which is our first attempt at implementing this vision. Youtopia coordination abstractions within the DBMS. Users submit queries that come with explicit coordination constraints to be met by other queries in the system. Such queries are evaluated together; the system ensures that their joint execution results in the satisfaction of all coordination constraints. That is, the queries coordinate their answers in the manner specified by the users. We show how Youtopia and its abstractions simplify the implementation of a three-tier flight reservation application that allows users to coordinate travel arrangements with their friends. Categories and Subject Descriptors H.4 [Information Systems Applications...