The black ball is from a Lego Star Wars series - there is another, heavier ball inside and it works as a counter-weight for the motor. The green guy is a creeper from Minecraft - purely for decoration. :-)
I don't know if I will be able to program it from Matlab, because both ways of communication with my Mac Book Air: bluetooth and USB are broken - Lego's drivers are not working.
If you wonder how Matlab programs look like, here is an example:
UPDATE 4 June 2015:
The course has ended. I passed enough quizzes and matlab programming tasks to get a certificate of participation and my clumsy robot made it too! Here is a mashup of the robots, mine is at 2:51: https://www.youtube.com/watch?v=FwCVHI9YOAw