Gravitational waves are among the most remarkable predictions of the Theory of General Relativity. Almost a century after Einstein first predicted the existence of gravitational waves, we are on the brink of directly detecting them for the first time. When the gravitational-wave window on the universe opens, the potential for discovery will be immense. Construction of the U.S. Advanced Laser Interferometer Gravitational-wave Observatory (LIGO) is well under way. Within the next five years, we expect to make the first detections of gravitational waves from binary systems containing neutron stars and/or black holes. I will give an overview of the new field of gravitational-wave astronomy: the sources of gravitational waves, our efforts to detect them and what we hope to achieve when we can observe the universe in this new way.