The video above is your only clue. Your mission, if you choose to accept it: find this signed and authenticated print of Banksy's "No Ball Games" within the next 30 days at one of the Art Series hotel chains -- snatch it without getting nabbed and it's yours to keep. The piece is stashed somewhere in the Melbourne area and worth $15,000 Australian.
Be warned, the artwork moves from hotel to hotel during the promotion's run so you'll either need to live out of a suitcase for the next month or excel at casing. Oh, and you'll need to be a guest at the hotel.
According to the hotel chain, the contest is being held to commemorate when, " in 2007, a group of bandits removed a section of a wall with an angle grinder because Banksy had stencilled around the 'No Ball Games' sign on it. The wall was later found on ebay for sale for 20,000 pounds." [Art Series Hotels]