Zillions of Games (1998, by Zillions, Inc.) is a board game emulator for Windows. It doesn't quite have zillions of games. But it could. Zillions comes with 48 basic games, simple games like Tic-tac-toe, complex games like Chess, different games like Senat, and just plain hard games like Ultima (yeah, that's where I learned it.)
Zillions comes with many pre-programmed variants of most of the games, like Petty Chess, Canadian Checkers, Beer Square, and about 240 others.
But the real beauty is not in the games it has, but in the games you can make. Zillions comes with an interpreter that can handle a board, 64 piece objects, tons of rules, and several different win/loss conditions for multiple players.
And there's something really outstanding here: you don't have to code the AI! Zillions looks over the rules, and develops a strategy, and when it's playing at the highest difficulty, it can crush most human players.
I haven't yet used the engine to make my own games, but I do know that it can handle infinite amounts of players. It can also do dice (by use of an imaginary player who makes a random move), and by that logic, I think it can handle card and other casino games, but I haven't seen any yet.