"The main science driver for our proposal is to develop novel algorithms to produce wide-field maps from radio-interferometric astronomical observations. The technique of Very Long Baseline Interferometry (VLBI) achieves the highest resolution of astronomical observations at any wavelength. Until recently, the size of maps produced by VLBI was limited to tiny regions on the sky. Based on our previous experience in pushing VLBI to larger fields, we will develop methods that allow real wide-field VLBI using affordable computer hardware. In combination with the development of new algorithms, we will use special-purpose hardware that was originally developed for graphics processing. This hardware, available in the form of high-end graphics cards, provides high performance for a low price and is well-suited for our applications. Using this type of hardware is currently also explored in other areas, and we plan to combine the main goal with other fields of astrophysics. Closest to the wide-field mapping project are applications in modelling gravitational lenses and calibrating and imaging data from the new LOFAR radio telescope array. On the more distant side, we will explore the opportunities for numerical N-body simulations, one of the active research areas at the host institute."