Mathematica Player 7.0Free
Mathematica Player is an innovative new take on viewer applications.
Rather than just a reader, like Acrobat Reader, or a thin runtime, like Flash Player, Mathematica Player has the full Mathematica engine embedded right there--ready to make documents come alive or to power applets. (Of course, don't forget it can read notebooks too!)
Because Player-interactive documents are so easy to make using Mathematica technology, thousands of these are already freely available at the Wolfram Demonstrations Project--with more supplied each day by researchers, educators, students, and professionals.