My friends dad woke him up once by pouring a gas can on him. When my friend realized what was going on, his dad was lighting a match and threw it at him.... The gas can was filled with water. Never overslept for school again.
I was sleeping on an air mattress & my friend dove onto the other side of the mattress, bouncing me up into the air. I woke up not touching the ground, weightless, falling. It sure got the adrenaline going.
Waking up from a 9 year coma to find you're in a hospital in Cyprus, and armed men are slaughtering the entire staff and patient base in an attempt to assure your death that should have come long ago.
By an alarm, 7:30 am on a monday morning
For those who have dogs or cats: "The sound of GUH GUH GUH GUH" as your dog is about to throw up all over your bed or your floor.