"Released alongside the Nintendo GameCube console, the standard GameCube controller has a wing grip design, and is designed to fit comfortably in the player's hands. This controller was bundled with all new GameCube systems throughout the consoles life cycle and was also available separately. It connects to the consoles controller ports via a 2m/6.5' cable.
The standard GameCube controller provides haptic feedback by way of a built-in rumble motor rather than using an external Rumble Pak add-on like the Nintendo 64 controller. Also unlike the it's predecessor, as well as it's successor the Wii Remote, this controller does not feature any expansion capabilities.
The controller features a total of six digital buttons, two analog sticks, a D-pad and two hybrid analog triggers/digital buttons.
The primary analog stick is on the left, with the D-pad below it. The four face buttons are on the right of the controller (a large green "A" button in the center, a smaller red "B" button below it and to the left and two kidney-shaped buttons; "X" to the right and a "Y" to the top) with a yellow "C" stick below those. A Start/Pause button is located in the middle of the controller. On the "shoulders" of the controller there are two analog triggers marked "L" and "R," as well as one digital button marked "Z" which sits above the "R" trigger. The "L" and "R" triggers feature both analog and digital capabilities. Each of these behaves as a typical analog trigger until fully depressed, at which point the button "clicks" to register an additional digital signal. This method effectively serves to provide two functions per button without actually adding two separate physical buttons."
Source: Wikipedia, "Gamecube controller", available under the CC-BY-SA License.