I heard this one about a year ago when it did the rounds here in the UK. It's originally from an Australian Radio programme.
Two OAPs were visiting an art gallery for their day out. They come upon this large painting of what seems to be 3 black men sitting on a park bench, but the one in the middle has a white penis. The 2 oldie goldies study this artwork for some time but still cannot fathom the meaning of the picture. Finally they spot the gallery curator and ask him to explain what the picture really signifies. The curator rather pompously explains at length that it's the latest artwork of a scottish artist and the white penis signifies the emasculation of the black race through it's history of oppression from european colonialists etc. etc. etc.
After a long and patronising lecture the curator leaves them, but the 2 pensioners are still staring at the painting with a bewildered expression when they are approached by a man who has overheard the explaination by the curator.
"Do ye want to know what it really means"
"And how would you know what this means?" they ask.
"I'm the man who created this piece of art" he says with a pronounced scottish accent.
"You see," he continued " it's really quite simple, all it shows is 3 scottish coal miners sitting on a bench for a break and the one in the middle popped home for his lunch."