This talk presents a novel approach to minimally invasive service differentiation in packet-switched networks. Instead of actively managing service allocation, a simple differentiated queueing algorithm provides traffic classes with essentially the same best-effort service that would result from plain FIFO service using a single queue for all traffic. However, each class is served from a separate virtual queue, which is configured with an individual deterministic delay bound that is enforced in the presence of dynamically varying packet arrival rates. The main advantage of such a scheme for service differentiation is administrative simplicity, because it only needs minimal configuration by a network operator and does not necessarily require control plane functionality. Further, it does not inherently prefer some traffic classes over others and thus satisfies even the most radical definitions of network neutrality. The basic approach is motivated with the help of various use case scenarios. A fairly simple and efficient algorithm is presented to implement the differentiated queueing scheme. Finally, a number of simulation experiments and results are shown that confirm the intuitive functionality of the algorithm.