How about trying to produce RGB signal for computer CRT monitor with FPGA in form of a Pong game? Done that.
This is part of a bigger project. We were examining if it is possible to build graphical user interface for the CNC machine ourselves using microcontrollers and FPGA chips. This was the display driver module of that project. As a test Pong game was used to demonstrate that it can be done.
Later it was decided that it would be too much work to do this all ourselves and ordinary PC was used as a user interface to the machine.