Teaching using GPUs is a challenge because of the need for special hardware and software resources. This is exacerbated when class enrollment is in the thousands. This talk showcases open source tools developed at University of Illinois - Urbana Champaign, and divulges some insights gathered while teaching to thousands of students from over 130 countries. Two tools will be presented: 1) WebGPU -- an online portal for GPU programming where students are presented with labs that test NVIDIA?CUDA?concepts. The students develop their code within the browser. The system then autogrades the submission. 2) RAI is an interactive command line tool used for project submissions. Students specify steps to run their project, which is deployed to a worker node and run within a container. Both systems are designed for fault tolerance, scalability to thousands of concurrent submissions, resilience to buffer overflows, and expansion using on premise or cloud compute resources.