Banksy is a pseudonymous England-based graffiti artist, political activist, film director, and painter. His satirical street art and subversive epigrams combine dark humour with graffiti done in a distinctive stencilling technique. Wikipedia
I love Banksy. I'm a bit obsessed with him actually. But did you know that he won't verify any of his street art now so that people don't go and rip walls down to try and flog it. You could just do a bit of stencilling on your front door and claim I was him. Who's going to tell you you're wrong ;)