When I was still slinging ink, I did a lot of tribal designs. They seemed to be very popular with the 90's generation of punker kids.
Tribal Tattoos are generally associated with the "Modern Primative" movement and incorporate a variety of artistic styles adopted from Aztec, Mayan and other ancient cultures. Most tribal tattoos are done in a single color, usually black with the most common being arm or leg bands.
Here's a design I did on a client several years ago.
It combines Mayan and Aztec styles.