The DK Bongos is a special controller that was designed to be used with the rhythm-based Donkey Konga series.
The controller is shaped like a pair of drums made out of barrels, which match the theme of the Donkey Kong games. It has two "pads" on each side, although it is known that each pad has actually two different parts to them. It also has a microphone in the center that detects noise such as clapping.
So far, all of the Donkey Kong themed games for the Nintendo GameCube have supported the DK Bongos, including the platform game Donkey Kong: Jungle Beat. The Donkey Kong games also work with standard controllers, but they were mainly designed for use with the DK Bongos.
The Bongos come bundled with the games that support it, but it is also sold separately.
Initially, the WiiWare title Plättchen Twist 'n' Paint was intended to have DK Bongo support, though Nintendo of Japan turned the idea down, stating that they want no Wii software (including games released online) to feature Bongo support. The Wii remake of Donkey Kong Jungle Beat did not feature Bongo controls but rather the player had to control it with the Wii Remote.
In Super Smash Bros. Brawl for the Wii, Donkey Kong's Final Smash Konga Beat will cause him to bring out the DK Bongos and jam on them. If you keep with the rhythm, it'll deliver more damage to the characters.