I saw some knit folk art left on a stop sign pole near Stanford Cantor Museum the other day. I saw Shepard Fairey “Andre the Giant Has a Posse” on a pole near Eric Cohen’s place in LA (Franklin Ave., area, near Upright Citizen’s Brigade) and on steps on tarmac for Southwest out of Burbank. I caught this wheat-paste job on the way to said airport. I thought it was by “See Her Hed” but may be confused. The Melrose/Fairfax blog could be a place for more info. Go, Banksy, at Oscars!!
http://melroseandfairfax.blogspot.com/
http://losangeles.ucbtheatre.com/
see her head sticker near Burbank airport
edit to add, December 31, 2011: Kimberly Chun of the Chronicle had a column item of a possible (read: doubtful) Banksy in Oakland.
Plastic Alto with Mark Weiss 
I think I mean septerhed:
http://www.septerhed.com/Blank.html
Magic of the high tech or as Bill Davidoff would say over-connected world is that now I know that Mateo Romero was tagged as being one of the plaintiffs who recently sued the Redskins football team AND that one of my favorite emerging artists Dogbyte is being mistaken for Banksy in LA.
http://melroseandfairfax.blogspot.com/2011/02/possible-5th-banksy-piece-in-la.html
gratuitous but here is Riggins scoring in Super Bowl freshman year and I recall a guy named Alex Rossides from DC jumping onto the table in front of the student union in front of the tv to dance a crazed jig at that moment.
http://www.youtube.com/watch?v=tleC3OYByXs
The knitting as graffitto piece was still on the stop sign pole across from Cantor Museum as of yesterday, March 16, 2011 which is also the birthday of Steve and Eric Cohen. Coincidentally I got a call from Christina Cohen (who could not reach her sons) with a question about Paul’s books that Steve and I carted in my truck from his office on the Quad. My recollection was that Steve, Eric, perhaps Charles and or Peter Sarnak had sorted and labeled the boxes of books, but I had not. (She and some math guy were sorting; the universe is ever-expanding and the six billion of us or are we one are still revising our story).
Back on topic here is LA Times on Shepard Fairey type take on Zuckerberg:
http://latimesblogs.latimes.com/culturemonster/2011/03/shepard-fairey-style-on-mark-zuckerberg-and-facebook.html