Internet routing suffers frompersistent and transient failures, circuitous routes, oscillations, and prefix hijacks. A major impediment to progress is the lack of ways to conduct impactful interdomain research. Most research is based either on passive observation of existing routes, keeping researchers from assessing how the Internet will respond to route or policy changes; or simulations, which are restricted by limitations in our understanding of topology and policy. We propose a new class of interdomain research: researchers can instantiate an AS of their choice, including its intradomain topology and interdomain interconnectivity, and connect it with the "live" Internet to exchange routes and traffic with real interdomain neighbors. Instead of being observers of the Internet ecosystem, researchers become members. Towards this end, we present the PEERING testbed. In its nascent stage, the testbed has proven extremely useful, resulting in a series of studies that were nearly impossible for researchers to conduct in the past. In this paper, we present a vision of what the testbed can provide. We sketch how to extend the testbed to enable future innovation, taking advantage of the rise of IXPs to expand our testbed.