GEO 600

LIGO [Laser Interferometer Gravitational-Wave Observatory]

LISA [Laser Interferometer Space Antenna] (see also here and here).

LSU Gravitational Wave Experiment (Louisiana State University)

MiniGRAIL [Gravitational Radiation Antenna In Leiden]

Rome gravitational wave research group

TAMA Tokyo Advanced Medium-scale Antenna

VIRGO

Other gravitational physics activities (see also here).