The Stroke is the only fair which is dedicated to Urban Art only. Mostly illustrations are exhibited. I have been to the Stroke 02. in Munich (May 2010) already. It was quite big, distributed on 5 storeys. Here are some impressions of the fair in Munich. So if you got time, just visit the Stroke 03. these days in Berlin, not as big as in Munich, but surely interesting!
the artists of Gallery Box 32, Berlin