It's like teaming peanut butter with jelly, or Chaka Demus with Pliers. For the first time ever, Kung Fu gods Jet Li and Jackie Chan join forces in The Forbidden Kingdom. The plot may not be earth-shattering - it's your standard 'time-traveling geek meets ancient Chinese warriors before learning Kung Fu and defeating oppressive overlord' narrative - but, with fight sequences choreographed by the incomparable Yuen Woo Ping (The Matrix, Kill Bill), this looks set to be a must-see Summer stunt fest. Just forget everything you know about the laws of physics.