We present a user-centered approach for prototyping tools for performance with procedural sound and graphics, based on a hackathon. We also present the resulting prototypes. These prototypes respond to a challenge originating from earlier stages of the research: to combine ease-of-use with expressiveness and visibility of interaction in tools for audiovisual performance. We aimed to convert sketches, resulting from an earlier brainstorming session, into functional prototypes in a short period of time. The outcomes include open-source software base released online. The conclusions reflect on the methodology adopted and the effectiveness of the prototypes.