  This paper presents the "Game Theory Explorer" software tool to create and
analyze games as models of strategic interaction. A game in extensive or
strategic form is created and nicely displayed with a graphical user interface
in a web browser. State-of-the-art algorithms then compute all Nash equilibria
of the game after a mouseclick. In tutorial fashion, we present how the program
is used, and the ideas behind its main algorithms. We report on experiences
with the architecture of the software and its development as an open-source
project.
