I originally wrote a prototype of this program during a weekend as sample code to show at a job interview. The interview didn't work out (selfish shameless plug: if you're hiring, please take a look at my resume), but something good came from it: MineSweeper! It took me another couple of weeks of work to complete/debug it, and here it is.
MineSweeper was/is, in the author's intentions (that would be me), a Java standalone application, from which the applet you see was obtained by removing all that functionality that did not comply to the applet security restrictions. If you like the applet, consider downloading and/or setting up the Java Runtime Environment (JRE) in your computer, in order to run MineSweeper in all its glory. You don't need the entire Java Developers Kit (JDK), as you can find a compiled version of the standalone application included in the source code downloadable from this page.