Saw the news on the BBC website (they cover science on the front page). Are there any of the major predictions of General Relativity left that haven't been observed, or was this the last big one?
Mercury's perihelion glitch: check
Bending of light: check
Gravitational redshift: check
Equivalence Principle: check
Gravitational waves: check
I'm not aware of any other predictions, but so far, quite impressive.