Ok, couple of things:
Gravity waves: physicists are spending large amounts of money on gravity infereometers to detect the presence of gravity waves. No-one has done so yet, but there is hope. Gravity wave detection is extremely difficult (if they even exist), because it is very hard to account for all disturbances possible. However, it is known that gravity, like other forces, travels at c (speed of light in a vacuum)
Tachyons: a postulated particle, never detected, whose important property is that it never goes slower than c.
FTL beams: Recently (Last summer), a group of physicists posted in Nature that they were able to fire a laser beam (laser beams are made up of photons, which are both wavelike and particlelike depending on what you are looking for) through a caesium filled chamber with a distance on the order of centimeters. The front wave of the beam contained all the information of the entire wave, and somehow caused an identical beam (although with much less amplitude) to be emitted from the far side of the chamber before the beam had fully entered the near side of the chamber. Measuring everything, these physicists were able to show the group velocity was much, much greater than c. Group veloccity is a hard thing to understand; it is very related to actual velocity, but is not the same. Take a couple of courses in Quantum Mechanics (an interesting subject in itself) and you might have a handle on group velocity. Anyways, these physicists believe that they did not violate relativity for various reasons. My best advice is to read up on this experiment yourself, for it is quite a well done experiment, and the results are still being interpreted.
The Japanese did the same thing, but with a much different wavelength of EM wave, and only exceeded c by 17% They are also not sure of what happened.
Kimball: I love it when engineers talk physics. It adds humor to my day...
Derek