Pub Games will give you a small taste of Fable II, but the three game modes wont soak up too much of your time.
The Pub Games are all about pushing your luck to win money for your character in Fable II. The first game you can play is called Fortune's Tower. Once you place your bet, the dealer will start dealing the cards in a pyramid fashion, one row at a time. The total value of the cards determine the value of that row - depending on how much you bet of course. As the number of cards increase in the rows, your chances of winning big get better. This game is the most entertaining and addicting to play.
The second game is Keystone. Keystone is a mixed version of craps and roulette. The table is a half circle with 16 arch stones on the edge with the numbers 3-18 on them. You start off by placing bets on the arch stones and then start inside betting. Inside betting is where you bet on what number will be rolled, if it's an odd or even number, black or red spot, pair, run, etc. This game is fun to play for a while, but if you play it in a tournament it'll take a very long time to finish.
The last game to play is Spinnerbox, which is similar to a slot machine. You simply place a bet and spin. Depending on what box you're using, a certain number of discs will spin; if you get a combo (usually 3 or more) then you win. Note: this is a very fast way to lose all your gold.
There is also a tournament mode to play. Simply choose which of the three games to play and you'll be placed up against some AI opponents. They're not that hard to beat, but that doesn't mean they can't come up from behind and score thousands of gold.
Fable II's Pub Games is a neat and fairly unique way to earn gold and items before you play Fable II. It'll cost you 800 Microsoft points ($10) if you didn't score yourself a pre-order download code. I wouldn't say it's totally worth $10 since there's only three games to choose from, but it does provide some addicting gameplay and could hold you over until the release of Fable II.