Pulsars are rapidly spinning neutron stars which emit beams of light, which can include radio waves, visible light, and even X-rays, from the magnetic poles powered by the neutron star's powerful rotation. We see pulsars as they seemingly "blink" on and off with extreme regularity as the beam rotates and points to our direction once every rotation. In fact, the regularity had astronomers thinking they may have discovered signals from an extraterritorial intelligence when pulsars were first discovered. Most pulsars discovered before now "blinked" in radio waves.
Via the Bad Astronomer, we hear news that the Fermi Gamma-ray Space Telescope has discovered a new kind of pulsar, one which only "blinks" in gamma-rays. One speculation is that it's not really a different kind of pulsar, but rather that the gamma-ray beam is more broader than the radio wave beam so that we only see it "blinking" in gamma-rays. This strikes me as odd since I would have thought it would be the other way around. Whatever the case may be, it's mind-blowing to consider the amounts of energy the pulsar must be emitting.