Master Mind

Five-Peg MasterMind
Play against the computer to solve the hidden color code in 7 guesses or less. Java applet.
http://chrisrusso.tripod.com/mastermind/index.html

Master Mind
Javascript verion of game, offered at two skill levels.
http://www.mah-jongg.ch/mastermind/

Super-Mastermind
Use logic to solve the secret code chosen by the computer in six guesses or less. Game requires JavaScript.
http://www.interjeux.net/jeux/mastermind/index_en.html

Three-Way Artificial Intelligence Mastermind
Online version of the classic board game offering multiple game settings for players of different skill levels. Play against the computer as either Codebreaker or Codemaker. Offers VBScript and JavaScript version.
http://home.pacific.net.hk/~kfzhou/mastermind.html