Remember the railgun that took down Devastator from afar in Transformers 2: Revenge of the Fallen? That was certainly a scene to remember, and I also think of the railgun in Quake 2 that would be able to pick more than one opponent simultaneously if they so happened to be in the way. The U.S. Navy is not too far behind such a fantasy weapon, as they have outlined plans to install and test a prototype electromagnetic railgun aboard a joint high speed vessel some time in 2016.
This particular test would be the first time an electromagnetic railgun (EM railgun) would be demonstrated at sea, which would mark yet another significant milestone in the world of naval combat, and I suppose that this would mark a change as huge as moving from boarding another ship to using cannons against one another.