I have always heard that nothing travels faster then the speed of light, but I recently read an article on Cerenkov Radiation, which states that it does travel faster then light.
Nothing can travel faster than the speed at which light travels *in a vacuum*. But, as explained here, it's possible to slow light down in a medium other than vacuum. In such a medium, it's possible to have a source of light that travels faster than light does *in that medium*. When this happens, you get the equivalent of a sonic boom for light: Cerenkov Radiation. You can read more about it here.