This article is based on ethnographic work with two "crews" of young graffiti artists in southern Mexico City. The crews share certain characteristics with gangs or urban tribes, but more with "communities of practice": they live in the "figured world" of graffiti, a community of practice at the local and global level. Through participation, including observation and the study of fanzines, group members learn the language, technical and social skills, and values of this figured world. Their reasons to paint and the topics they express are varied, but authentic expression is fundamental. Graffiti allows these young people to establish an interesting interplay of identities in the world of graffiti versus their ordinary lives. (Contains 8 photos and 1 illustration.)