This website provides the URL of a Java applet and steps for using it. Here, students can manipulate the size of the circle and the rectangle to explore the probability that a point in the rectangle is also in the circle.
The BUGS (Bayesian inference Using Gibbs Sampling) project is concerned with flexible software for the Bayesian analysis of complex statistical models using Markov chain Monte Carlo (MCMC) methods. This site is primarily concerned with the stand-alone WinBUGS 1.4.1 package, which has a graphical user interface and on-line monitoring and convergence diagnostics. This program can be downloaded for free from the site.