Wikipedia
PokerTH
PokerTH is an open source Texas hold 'em simulator that runs on Unix-like operating systems such as Linux, BSDs, OS X, Android and also on Microsoft Windows. The game is faithful to the Texas Hold 'em rules and betting system. PokerTH allows for up to ten human players, with computer-controlled players filling in if there are not enough humans. Players can also play against other PokerTH users online. The latest stable version, 1.1.1, was released on 10 January 2014.
The game has ample settings so that players can configure and customize play.