How precisely can we measure and control the motion of an object? Quantum mechanics gives a famously unsettling answer: the act of measurement inevitably disturbs the motion we seek to measure -- this is the famous uncertainty principle of Heisenberg, theorized almost exactly 100 years ago. I will describe recent experiments that approach these limits using tangibly macroscopic mechanical oscillators, including the measurement and quantum control of motion of a kilogram-scale mirror, and of a centimeter-scale torsional oscillator. At these scales, quantum mechanics becomes a theory we can test with objects we can see and weigh--opening the possibility of asking whether quantum mechanics survives unchanged in the macroscopic world, and ultimately whether gravity itself must obey quantum rules, one of the pre-eminent problems of modern physics.