GPUs are now massive floating-point stream processors that offer a source of energy-efficient compute power on our laptops and desktops. Recent development of tools such as CUDA and OpenCL have made it much easier to utilize the computational power these systems offer. However, in order to optimally harness the the power of these GPU-based systems, there still are many challenges to overcome. In this talk, several issues related to our experiences with medical and geological processing applications that can benefit from real-time processing of data on GPUs, will be discussed. These include real-time medical imaging, e.g. for ultrasound-guided discovery and surgery, real-time seismic CT image enhancement, and using GPUs for real-time compression of seismic data in order to lower I/O latency. This talk will highlight work our research group has been involved dating back from 2006 through today.