Welcome aboard Gracy. Welcome to LQ!
I believe you should try to think about the things you like, things that inspires your enthusiasm (Open Source did for me). But for a suggestion, how about an open source bandwidth management program?
Bandwidth monitoring are out there in numbers. And there are few user-space bandwidth management tools around. And we have quite good network management tools. But there's no proper open source tool for banwidth management wich would stand up to commercial counterparts with GUIs, real time monitoring and dynamic rules, and etc. So why not think about a such, at least a start (maybe utilising HTB - Hierachical Token Bucket).
is somewhat a starting point. There are a few more things in the Net. If you are interested they may come in handy. (However if everything moves as expected I might
start a little project regarding this area next year)
This is one thing I could suggest.