I just finished the C Piscine at a 42 school, so I have gotten a good grasp of the basics of C (about 300 hours worth). The school won't start until October, and I'd like to practice my C skills in the meantime so I can be better prepared when it does start.

Any suggestions for curriculum / projects that don't start at the very beginning? I already have a good grasp of pointers, control structures, structs, string manipulation, etc.