As mentioned already, Illuminati Deluxe is a card game, though in a sense it's a tile-laying board game disguised as a card game.
Each player is one of the great secret ruling societies, or Illuminati, of the world. Using your influence, money, and unique power you work to meet your unique goal (or the general goal of all of the Illuminati, to wield a certain amount of power).
A lot of the fun of the game comes from the hilarious groups you control (like the Gamers, the Boy Sprouts, the Fiendish Flouridators, etc.), the funny way that you indirectly control most of your groups (you might control the CIA, who in turn controls Texas, who controls Television Evangelists, who control the Boy Sprouts/Scouts, and since every group is kept in the dark about who controls what, the CIA doesn't realize they're a tool to control the Boy Scouts, all of whom are controlled by you, the UFOs), and from the fact that to win you must form a lot of temporary diplomatic alliances.
The game's downsides are that the element of luck is a bit too much (if you draw one of the weaker Illuminati or if you draw bad groups it can be impossible or nearly-so to win), there's a problem where most of the time people know how close you are to winning so when you get close everyone gangs up to take you down a couple of notches (so the game can run for many hours), and there's a significant "kingmaker" factor, where a player can work to throw the game to another player and nothing in the rules prevents it.
Still, it's great fun. In college I played it 3-4 times a week for a couple of years and we always had a great time (the optional cheating rule really keeps you on your toes), and I still get it out to play once or twice a year now.