|Style over substance|
The EmDrive is a "method" of spacecraft propulsion developed by Roger Shawyer. The inventor claims that it works by flooding a resonant cavity with microwave radiation. The radiation exerts pressure on the walls of the cavity, and due to "relativistic effects," the cavity (shaped like a truncated cone) will experience a larger force against the large end than the small end, due to the group velocity of the wave changing as the local diameter of the cavity varies. The inventor claims that this will cause the engine to be propelled through space. He also claims that the engine does not violate the laws of physics, even though it does. Specifically, as a "reactionless" drive, it violates the conservation of momentum; as every action has an equal, but opposite reaction, to propel a craft requires something to shoot off in the other direction.
Several prominent physicists have said that it is impossible, but that didn't stop China from trying to build one anyway, following in the footsteps of a British company that tried in 2004. It is unknown exactly how annoyed they will be when it doesn't work. The invention is on the same level of lack of common sense as Time Cube, though the latter website has better formatting.
New Scientist wrote a rather favourable article on it in 2006, although they later made a note on the New Scientist blog that they should have more thoroughly covered the criticism of the drive. There is a video supposedly showing it in action.