Against my better judgment I have let some of my GCSE student choose graffiti as a topic for their Art exam. In order to get a good mark they need to research widely, choosing to look at the less obvious sources. They must draw from life, and they must choose at least one artist to study. They must not, use graffiti generator online, they will NOT get you a GCSE, they must not spend the next 7 weeks repeatedly designing a tag of their name.
I will post some profiles of famous graffiti artist.
This links to a site thats shows some different types of graffiti, if you chose this topic, read this link !
http://weburbanist.com/2009/09/24/graffiti-designs-styles-tagging-bombing-painting/