Out-of-time-order correlation functions are of theoretical interest for diagnosing the scrambling of quantum information in black holes and strongly interacting quantum systems generally. I will describe a general protocol for measuring them which requires an echo-type sequence in which the sign of a many-body Hamiltonian is reversed. I will discuss an implementation employing cold atoms and cavity quantum electrodynamics to realize the chaotic kicked top model and will analyze the effects of dissipation to verify its feasibility with current technology. Following some comments on subsequent proposals and on two preliminary experiments, I will conclude with a survey of some recent calculations of out-of-time-order correlators and what I think we might learn from experiments.