This is a shiny application that provides a point-and-click interface for charting tennis matches for the Match Charting Project.
The Match Charting Project (MCP) is lead by Jeff Sackmann of TennisAbstract and Heavy Topspin. More about the project can be found on Jeff's sites. The aim of the GUI is to help new charters get involved and complement the other tools for charting that are already available.