I will describe the physics of graphite crystals with rhombohedral stacking, where the competition between electron hopping within- and between- the graphene planes leads to a flat electronic dispersion and the crystallinity leads to a near total absence of disorder.  The high electronic density of states and Berry curvature—-both of which can be tuned by a perpendicular electric field—lead to a dizzying variety of magnetic and superconducting states, often within the same device, while the high experimental reproducibility enabled by the crystalline nature of these structurally simple systems allows us to investigate a variety of correlated electron phenomena.  I will focus on our efforts to use scanning nanoscale magnetometry to probe the nature and origins of magnetism and unconventional superconductivity, as well as the fate of the correlated electron liquid at high temperatures.