A cajón (Wikipedia) is an Afro-Peruvian percussion instrument that consists, essentially, of a wooden box with at least one thin plywood “playing face.” The other five sides are commonly made of thicker plywood, and most designs feature a sound hole cut in the face opposite the playing face. Often, the top edge of the playing face is left unattached to the sides, and snares (like those on the underside of a snare drum) may be stretched across its inner surface.
In the embedded video, percussionist David Kuckhermann shows off what this seemingly humble instrument can achieve in the hands of a skilled player. There are many online tutorials for building cajónes (not to be confused with “cojones,” por favor), but I especially like this one from The Cajon Drum Shop of South Shields, UK. [Thanks, Ben Ehlers!]