Massive early-type galaxies (ETGs) are often assumed to be ‘red and dead’ systems, which have been passively evolving since z~2. In fact, many such systems host residual star formation and contain large cold gas reservoirs. I will show how observations of the cold and warm ISM, combined with simulations and models, can be used to shed light on the mysterious origin of this material which changes the late-time evolution of red-sequence galaxies. I will show that star formation in these objects is dynamically suppressed, leading to stars forming with a much lower efficiency than in spiral and starburst galaxies. Star formation is also suppressed in ETGs which have undergone a recent minor merger. These dynamical processes that suppress star formation are likely to be important in other galactic nuclei, and perhaps even in our own Milky Way. Finally I will show that molecular gas is an excellent kinematic tracer, providing a powerful tool for both studying the large scale mass distribution in galaxies (e.g. with the CO Tully Fisher relation), and probing dark objects lurking at the hearts of galaxies. I will show, using high-resolution interferometric observations, that one can resolve molecular gas kinematics within the sphere of influence of local supermassive black-holes and present the first ever black-hole mass measured in this manner.