Thought I'd share a educational game I developed in partnership with Stetson University. Essentially a mahjong type game using chemistry knowledge.
Now's there an iPhone/iPad version too:
Pretty simple, but students love it and we found some great sound effects from the Free Sound Project.
The games were known to be addictive, since the first humans came to know each other and the Internet plays a role in making popular and easy to play and shop became even more popular. Many varieties of games have come and gone, but Mahjong is a game, for example, still holds the same status to be addictive. But have you ever wondered how it is possible that online Mahjong Mahjong forum to be so popular, even in modern console games like Guitar Hero, Call of Duty, Singstar, etc. The reason is simple, it has the ability to stay stuck to it with eyes wide open looking like stones. Besides the simplicity of the game, the main reason for their success is available.