Now this is clever: Card Table (free) really isn't a card game. As the developer says, "It's every card game." What you get is a virtual deck of cards. Your iPad is the table, and an iPhone or iPod touch holds your individual hands. You can move cards between devices with a swipe, so you can see a card leave the iPad and slide over to an iPhone. It's nice for lots of card games like poker, blackjack, spades, bridge or any game that works with a 52-card deck.
You connect with Bluetooth or Wi-Fi, and the iPad needs a Game Center account. There's no server in the mix -- everything passes between your iOS devices. That's all there is to it. You can shuffle the deck, choose the card backs and fronts, and set the positions of the iPhones around the table to match your physical locations.