Just some old saying that I would like to share. This was followed by some of us but some who know it still did not believe in it. For me, I accidentally follow this as I usually sleep quite late due to my hobby to online.
By the way, this thing is all about some black magic learned by some of the people out there. In old believes Black Magic is known to be powerfull between 12midnight until 12.30 midnight. At this time the person with Black Magic ability will actually do all the ritual to send some bad luck to the person targeted by the clients.
Normally they will send it by using the air but at some other style, if you are being targeted and you are sleeping at this time they will actually called your spirit and do some bad thing to it in which will caused you to get sick or what so ever they want.
Even so 12midnight to 12.30midnight was the best time to send bad luck, the thursday will also be the best time for the spell to be success. The period is also the same but as foretold, the whole thursday night to friday dawn, will the most powerful time for it.
So the best is to sleep after 12.30midnight or 1am. Anyway, this is just a story told to me. Believe it or not, that will be depends on you.