  We have been undertaking a programme on the Gemini 8-m telescopes to
demonstrate the power of integral field spectroscopy, using the optical GMOS
spectrograph, and the new CIRPASS instrument in the near-infrared. Here we
present some preliminary results from 3D spectroscopy of extra-galactic
objects, mapping the emission lines in a 3CR radio galaxy and in a
gravitationally lensed arc, exploring dark matter sub-structure through
observations of an Einstein Cross gravitational lens, and the star formation
time-scales of young massive clusters in the starburst galaxy NGC 1140.
