The Kano Durbar is a fantastic festival and procession held regularly in Kano, Nigeria. Featured in the processions are thousands of horsemen in antique ceremonial gear - the horses wearing ornate bridles and saddles; the men in billowing colorful robes and turbans. According to this article, the durbar was encouraged by the British during colonial times as a way of redirecting the efforts of warring factions into a unified ceremonial event. The durbars are held on major Muslim holidays, but also staged for special occasions, such as visits by important dignitaries. The northern part of Nigeria, where Kano is located, is a Muslim area, and the horse culture reflects a mix northern African and native Nigerian styles (Islam spread into Nigeria from its origins in Arabia via the Saharan trade routes).
This site has a gallery of nice pictures of the processions. The fabrics used in the clothing are spectacular, as are the beautiful bridles on the horses.
This photographer's site has some really stunning photos, including close-ups of the horses and regalia.
Photo above: whereiseggy on flickr.
Thanks for the tip about the durbar, Ot!