Armed robbers steal Munch's "The Scream" from a crowded museum
Maybe I've seen too many movies, but old-fashioned heists capture my imagination.
Witnesses described the thieves as clumsy, even dropping the paintings on the way out.
I'm thinking of A Fish Called Wanda and Palookaville here.
Good list of 20th century art heists:
http://news.bbc.co.uk/2/hi/entertainment/3590106.stm