I agree with @hackerboos, definitely write a c-extension. It will not only enhance your knowledge of python but you will also learn C/C++ during the development. I did something similar wrote a ruby c-extension https://github.com/chaitanyav/fibonacci for fun. Also, checkout the CS107 videos on youtube which are C based (look for cs107 stanford).

you can also try writing the core utils using your newly learned C/C++ skills.(https://github.com/chaitanyav/cprograms)