Mahjong is a four-player game sometimes called "Asian poker".
Here are some slides (PDF) with a gentle introduction.
Great for practice. There is also a bamboo-only version if you want to practice complicated waits.
Minefield Mahjong is a two-player game I made with some friends. It's also available on Github if you want to play with the code.
See also the poster (PDF) describing the implementation!