Shepard Fairey, Ron English, Kenny Scharf and Robbie Conal guest star on an upcoming episode of the Simpsons - Exit through the Kwik-E-Mart! Broadcast is on March 4th. 

I spied this on the Obey Giant site, which has a short plot synopsis: "In order to get back at his dad, Bart goes undercover as a graffiti street artist and plasters homer's unflattering image all over Springfield. But one night, Bart and Milhouse get caught in the act by established street artists Shepard Fairy, Ron English, Kenny Scharf and Robbie Conal (guest voicing as themselves), and to Bart's surprise, they invite him to exhibit his satirical artwork in his very own gallery show." Can't wait - March 4th, pretty much everywhere...

Via Obey's website