What causes sleeping while sitting up?

I have had sleep walking issues on and off sense i was about 6 (i'm 19 now). And i get REM sleep (rapid eye movement) a lot! ...

Do you talk in your sleep? I definitely do.

like at night my blanket will be on the right way and when i wake up it will be a different way. why is that?

Is there a Mathimatical realation between how long you stay up ( like several days) and how long you sleep when you do fall a...

Every time I go to sleep I wake up with my head underneath the covers. It's weird. What does that mean?

I sleep talk. It can get pretty embarassing. I talk about some pretty crazy things. Is there a way to stop it?!

How many of you are still sitting infront of your computer screens eventhough it's midnight?I am.

im bored so here's a riddle. When I go in I cause pain. I cause you to spit and ask you not to swallow. I can fill your hol...

how can you prevent yourself from sleep talking? my sis does it :]

I never actually knew what caused the tower to become the leaning tower of pisa... does anyone know?