You probably could have guessed that the truck sitting outside three major Manhattan art fairs would be packed with "street art" as a "mobile art-fair booth," a kind of alternative to all the consumerism art-fair season brings. What you probably didn't expect is that the artists inside would be worth a hoot. In this case, the pieces come from such notable names as Swoon, Shepard Fairey, Faile, Bast and Banksy (remember him?). Catch the Louvre-ish lorry parked outside the Armory Show on the corner of 53rd Street and Eleventh Avenue.