The LIGO Scientific Collaboration and Virgo Collaboration just announced the second detection of gravitational waves. The detection paper can be found in Physical Review Letters. As with the first event the source was the merger of two black holes. This time the mass of the two components was 14.2 and 7.5 solar masses and the signal was observed for 55 cycles lasting ~1 second.
There will be a lot written about this event in the coming days. There is a nice summary at soundsofspacetime.org.