SmartMines is a minesweeper game for Mac OS X (Tiger and above) with a few features that make it stand out when compared with many other minesweeper games. For instance, it features "smart clicks" that make it easy to both mark and uncover with single button mice. Also the minefield window is resizable, so actually hitting the square you want will not be the greatest challenge.
Card Monsters lets you play a creatures, instants, and sorceries. You to play the game against a computer-controlled opponent. Currently there are over 300 cards, and you can play in constructed, sealed, and draft mode. The program can automatically download all of the card pictures. The GUI is basic but very usable.
MyMahj is a relaxing solitaire Mahjong game in 2D and 3D. The purpose of the game is to clear the screen of tiles by clicking on two identical tiles (or two seasons or flowers). Only exposed tiles can be removed at any given moment. A tile is exposed if there is no tile over it, and if there is empty space on its left or right side.
Java Games is a collection of simple games that are compiled into Java applets and meant to be played online in a Web browser. Currently the collection contains four games: XO World (similar to tic-tac-toe, but with lines of 5 on a 10x10 board); 100 Mack (guess the random combination of 4 images out of a set of six); Memory (flip 2 plates at a time to find matching pairs); and Tetris.