The most popular Yahoo! Games are categorized on the main Games page. To find all other games, just click on the "All Games" link in the category you're interested in. Then just click on the name of the game you'd like to play.
For other games (like Pool and Spades), you'll be taken to the game's ante room (where you'll find the list of lounges). From this ante room, select a gaming lounge based on your level of play (social, intermediate, or advanced). Once in a lounge, you can get information about the specific rules of the game, select your screen size, and choose the identity you want to play under. After entering a gaming room, you can join a table in progress, create your own table, or watch a game in progress. Click “Play Now” to automatically go to a table with an open seat. Or, any table with a "Join" button needs players and you can click the button and join the table if you'd like. If you create a table by clicking the "Create Table" button, you become the host and you have the option of inviting other players to the table using the "Invite" button. To watch a game, click "Watch" next to an active game.
Please note that getting into a Bingo game is slightly different. As usual, click "Join In" to join a table. However, currently you cannot create or host a Bingo table like the other games.