I normally put my powerbook to sleep overnight and have it in my room on my bedside table.
Twice in the past week, it has woken up at 2.57am and scared the shit of out me!

Why would this be happening? And how can I stop it?!?!?!?

Close the lid!

My MBP did this to me the other night too! Gave me a right scare... but I figured I just hadn't closed the lid properly.

Unless it is haunted?

stupid question, have you somehow activated the inbuilt function of mac's to turn on when you want them to?

its under energy saver in system preferences, then under schedule.

This gives you the option to sleep/shut down/wake your computer whenever you want.

You should check that there aren't any values i nthere, and someone isn't playing a trick on you :P

It is most likely the daily maintenance scripts running.

My iMac does this on a Friday night at about the time you are describing. I figured it was maintenance scripts as it is a regular thing. You can check you logs to see when the daily, weekly and monthly scripts were run.

OK so it's probably the maintenance scripts.
Can I stop them running when the computer is sleeping?

My imac has been turning it's self on during the night. For a while I thought I was just losing the plot. But I actually shut it down (with a witness) and when I came out in the morning it is asleep (showing it has turned on, sat around, and gone to sleep).

I've checked the function in power save where you can set it to turn on by it's self, and have had a look through most setting in case there is a "wake for network access" or "automatically re start after power failure" sort of thing that may be causing it...

It's no biggie, I just kill the power at the wall, or leave it running to download stuff.

This was happening with my old sawtooth a month or so back, ie it was waking from sleep spontaneously. First time, it happenened around 3.15am, which I think is the time when one of the maintenance scripts runs. Started to happen at other times after that and more often too.

I checked the power settings in preferences and all seemed ok.

I then changed the logic board battery, was 7 years old. Happened again, zapped pram (which I hadn't done) and touch wood, its been ok since then.

I had thought it might be something happening in the power supply also. So I did have that out at the same time.

Looked all over the forums and couldn't find anyone who had had the same problem.

Any update on this ppops, I'm interested to hear if you have a solution ????

This happened to me for aaages and I didn't know what was causing it, until I checked out my EyeTV and realised that the software was set to update its recording schedule every hour. Turned it off and all was good!

Nope, I don't think so. Hasn't done it for a few days though...

I did uncheck "wake for network access". Maybe that has stopped it. Too early to tell.