Ibis is an open source software framework that drastically simplifies the process of programming and deploying large-scale parallel and distributed grid applications. Ibis supports a range of programming models that yield efficient implementations, even on distributed sets of heterogeneous resources. Also, Ibis is specifically designed to run in hostile grid environments that are inherently dynamic and faulty, and that suffer from connectivity problems. Recently, Ibis has been put to the test in two competitions organized by the IEEE Technical Committee on Scalable Computing, as part of the CCGrid 2008 and Cluster/Grid 2008 international conferences. Each of the competitions' categories focused either on the aspect of scalability, efficiency, or fault-tolerance. Our Ibis-based applications have won the first prize in all of these categories. In this paper we give an overview of Ibis, and — to exemplify its power and flexibility — we discuss our contributions to the competitions, and present an overview of our lessons learned.