I start a little championship here to see what combination of applications (can be anything, ie. your own python scripts) need to be run in order to deplete the battery fastest.

Rule 1. Fully charge the battery
Rule 2. Start programs
Rule 3. Go until you get the low battery warning
Rule 4. Report your results

This is the first contestant, which I believe will be very easy to beat:

I've been watching 6x45 minute 1024 bit divx/128 bit mp3 640x480 films with BT off, wifi scanning at 10 minutes. Total time to deplete battery: 270 minutes.

I know how to do it without all of that!

Try to play the Flash game, Afterglow. It is a lunar lander kind of game, but hangs at the menu. You can close the browser, but it will hang on anyways and browsersd will take about 80-90% of CPU and audiopulse will take about 8-10%. The steady 90 to near 100% just from those two processes will suck the battery down in no time and amaze you how hot the N900 can actually get

This happened to me, so is how I know

Screen brightness to full, start filming in the dark. Does it for me.