Over the past few years, the physics of low dimensional electronic systems has been revolutionized by the discovery of materials with very unusual electronic structures. Among these, graphene has taken center stage due to its relativistic-like electron dynamics and potential applications in nanotechnology. Moreover, the recent discovery that hexagonal boron nitride (hBN) is a nearly-ideal substrate for high mobility graphene devices has enabled a new generation of quantum transport and optoelectronic experiments in graphene-based materials. In this talk I will review our recent experiments on graphene on hBN devices, where we explore different aspects of the "Dirac-ness" of charge carriers in graphene: from novel optoelectronic phenomena to a new type of quantum spin Hall effect.