If you understand Formal Specifications, then you can possibly pick up an existing project and try to improve it.
Usability/ Documentation projects can also be very useful.
You can try hardware hacking projects too. Some scanners are nearly supported, but some modification of source must be done in the back-ends. You can try those. E.g Scanners in the UMAX Astra series
But first, how many hours are you supposed to put into the project?
NRC-FOSS can also sponsor your projects. Have you checked that?