What do you do when you wake up at four am?
Usually for me it means writing. I am doing my Bachelor´s thesis and some days there is a clock inside me that wakes me up at four am. At this point, it is the best time to actually get some progress in my thesis and other courses that are still unfinished. I don´t know why my inside clock can´t wake me up an hour or two later?
On the other hand, there is not much you can do at that time without waking up everybody else.