Imagine that you can decide about what you want to do a project and improve your knowledge. I mean, you can choose learn about rfid, controlling motors, pid, sensors... all under arduino interface. This is SMALL ROBOT DESIGN IN CVUT.
In my case I chose to implement a gps in a quadcopter and my teacher was agree with the difficulty. User should send coordenades to quadcopter, it should receive, compare with onboard gps and change the speed motors to achieve the desired position. Some classmates decided to do the other stuff with the quadcopter: stability pid controller and data transfer.