Reversi Mania 3 : Othello is pretty nice

Othello is an easy to learn, hard to master board game. There are many software versions to play with, but, this one, is really pretty and have a relaxing soundtrack. For advanced players this version is not the game of choice, the AI is not really hard to beat, but if you want a casual 5 minutes play, don't look elsewhere. In case you're a real hardcore reversi player there is K-Reversi. Not as easy on the eyes as Reversi mania 3 but way harder, even in the easiest difficulty settings. Moreover it keeps track of every play done.

Reversi on the wikipedia

Platform : PC
Cost : freeware, doujin

Downloads :
Reversi Mania 3, Click on the picture
K-Reversi, click the krev04.lzh link