Computer-based simulations of complex natural phenomena and man-made artifacts are increasingly employed in a wide variety of sectors. Typically, such simulations require computing environments which meet very high specifications in terms of processing units, primary and secondary storage, and communication. Supercomputers constitute the de fact technology to deliver the required specifications. Acquiring, operating and maintaining supercomputers involve considerable costs, which many organizations cannot afford. The working assumption of the QosCosGrid project is that a grid could be enhanced by suitable middleware to provide features and performance characteristics that resemble those of a supercomputer. We refer to such a grid as ‘quasi-opportunistic supercomputer’. The QosCosGrid project is currently developing such a system. More details on the expected and actual results of the project published here.