How did I know this is what you two would be doing? To try and salvage this, PS1 and PS2 games greatly benefit from emulation. If you have played and enjoyed some, try them out with a maxed-out emulator. You might enjoy them more. EDIT: Disregard this post
Building your own CPU with its own instruction set and stack etc, is a useful learning experience on how CPUs work in general. Other than that, its not of much use though.
You should try to make some stupid programs for fun and benchmark. Fibonaci? Listing primes? Video output with a cube rotating? Crysis 3?