Any ideas for c++ projects for junior?

i have learned something about c++ (OOP + now during studying STL) and I want to start a project which i would put to my resume, becaouse in the future I would try to apply to a internship or junior position. I have created a lot of simple projects like algroithms, little games, numeric algorithms, SPOJ exercises etc but in my opinion it was to small to put into github. Have you any ideas for projects what can i program to get some real experience? I tried Python, some WebDev(Java+Spring) etc but i want to stay with c++ right now. I thought about maybe chat(networking) or my own STL? What you think?