DIET is a software for grid-computing. As middleware, DIET sits between the operating system (which handles the details of the hardware) and the application software (which deals with the specific computational task at hand).
GridRepublic Alternatives
GridRepublic is described as 'Customized version of the BOINC software designed to simplify installation and participation by the average computer user' and is an app in the education & reference category. There are more than 10 alternatives to GridRepublic for a variety of platforms, including Linux, Mac, Windows, Web-based and Android apps. The best GridRepublic alternative is BOINC, which is both free and Open Source. Other great apps like GridRepublic are Apache Mesos, Charity Engine, Folding@home and Foldit.