Timbales are cubano/brazilian drums with metal shells and open bottoms rather than bottom heads. They are almost always seen in pairs, on a rack, often with a cowbell set up in between. The range of sounds one can get from these drums is impressive, and if played well, these drums are amazing to hear. To hear really really good timbale playing, check out Tito Puente or Don Elias. Santana's old stuff all has good timbales, as well (much of it played by Puente).