Final year of what? Do you need to show competence or originality? Write a paper or just build something cool? Maybe just a simulation, they are _so_ much easier...
But I've been working with small real robot cars, so here're a few ideas.
First, the fire-fighting competition: http://www.trincoll.edu/events/robot/
next, soccer: http://www.robocup.org/
and last, I just remembered this paper that was probably never published that modeled a chaotic exploration behavior:
http://www.santafe.edu/media/cms_page_media/261/Meisburger_final_paper.pdf
maybe you could implement it?