CMOS pixel electronics open up for applications with single photon or particle processing. TIMEPIX3 is a readout chip in the MEDIPIX family with the ability to simultaneously determine energy and time of interaction in the pixel. The device is fully event driven, sending out data on each interaction at a maximum speed of about 40 Mhits/s. The concept allows for off-line processing to correct for charge sharing or to find the interaction point in multi pixel events. The timing resolution of 1.56 ns allows for three dimensional tracking of charged particles in a thick sensor due to the drift time for the charge in the sensor. The experiments in this presentation have been performed with silicon sensors bonded MEDIPIX family chips with special focus on TIMEPIX3. This presentation covers basic performance of the chip, spectral imaging with hard X-rays, detection and imaging with charged particles and neutrons. Cluster identification, centroiding and charge summing is extensively used to determine energy and position of the interaction. For neutron applications a converter layer was placed on top of the sensor.