Analyzing the evolution of large and long-lived software systems is a complex problem that requires extensive tool support due to the amount and complexity of the data that needs to be processed. In this paper, we present Churrasco, a tool to support collaborative software evolution analysis through a web interface. After describing the tool and its architecture, we provide a usage scenario of Churrasco on a large open source software system, and we present two collaboration experiments performed with, respectively, 8 and 4 participants.