Seeing this thread is slowly going to become this, I may as well contribute:
When I was a kid I didn't have an alarm clock, so my sister and I came up with what we thought was the smartest idea in the world
On the shelf above my bed she put one of her Ken dolls (cos I wouldn't have barbie apparently...), and tied a piece of string to it and dangled onto my bed. The point was that at exactly 6AM (prime cartoon time), i would roll over and tug on the string, pulling on the ken doll which would come crashing down onto my head, thus waking me up. It never did, nor did I ever roll over onto a piece of string at 6AM
Goddamn what a retard I used to be
(edit: best to say here that my original idea was to use a rather large rock. I'm glad it didn't work out for that one)