I love going around my town and shooting textures for my Textures4Photoshop website. One theme I really enjoy shooting is graffiti drawings on walls.
I found this really awesome old wall and old door with some graffiti designs on it and decided to do more than take a photograph, so I tried my hand at photogrammetry - this is a technique that produces a 3D model from multiple photos. This is the end result I got with very little cleaning up in Blender 3D.
For graffiti textures check out Textures4Photoshop: http://www.textures4photoshop.com/tex/tags/graffiti.aspx