PowerPoker is a really great poker game for classic Mac OS. It has over 100 different games. You can highly tweak the rules, the chips, the tournaments, the look of the board, you name it. 

Nothing need to be installed to play this game, you can play it right off the disc. Or you can copy the app to your hard drive and play it directly. I've never witness it crash. Works in System 7, Mac OS 8 and Mac OS 9. It looks like you can also play network games over an AppleTalk network, but I've never tried it. 

Only the original disc is included, no case or manuals.