tofu,

Try this experiment, verbally tell yourself out loud that you want to wake up at a specific time. Not the time you usually get up, but some other time. Ex. If you get up a 6 am, then verbally tell yourself out loud to wake up at 4 am.

I've done this several times when I need to wake up on the weekends for some special reason. It works for me and I'm only 34.