Hybrid pixel detectors, first developed as tracking detectors for the LHC experiments, have found numerous applications both inside and outside the domain of High Energy Physics. The Medipix and Timepix readout chips are used in classrooms, at synchrotron light sources, as mixed field radiation monitors on the International Space Station and in many other applications. Most recently clinical trials have started in the domain of medical spectroscopic X-ray radiology, an imaging modality made possible by the detection of X-rays one by one. The devices are also commercially available and have led to the creation of a number of high technology start-ups in the CERN member states and beyond. The devices are used at CERN in experiments studying transition radiation, as detectors of anti-matter and as beam monitoring devices. This seminar will provide an overview of the Medipix and Timepix devices and describe some applications.