Modeling and simulation with petascale computing has supercharged the process of innovation, dramatically accelerating time-to-insight and time-to-discovery. The Titan supercomputer is the Department of Energy’s flagship Cray XK7 managed by the Oak Ridge Leadership Computing Facility (OLCF). With its hybrid, accelerated architecture of traditional CPUs and graphics processing units (GPUs), Titan allows advanced scientific applications to reach speeds exceeding 10 petaflops with a marginal increase in electrical power demand over the previous generation leadership-class supercomputer. I will summarize the lessons learned in deploying Titan and in preparing applications to move from conventional CPU architectures to a hybrid, accelerated architectures, with a focus on early science outcomes from Titan. We will discuss implications for the research community as we prepare for exascale computational science and engineering within the next decade. I will also provide an overview of user programs at the OLCF with specific information how researchers may apply for allocations of computing resources.