Italy's OPERA experiment may prove that a particles called Neutrino can travel faster than light. It's rare for these particles to interact with normal matter, they pass straight through earth as if it were a vacuum.
If a particular like Neutrino can exceed light speed, the rules of physics could be invalidated, and Einstein's special theory of relativity " E = mc^2 " which averted the possibility of anything breaking the speed limit and nothing can travel faster than the speed of light -> need to be revised! If this turned out to hold true it'll be possible one day to "time travel" ta ta ta ta!