I have an Olympus Camedia D-595 Zoom (I know! sounds like an STD!!!) - it a 5mg pocket camera, and in manual mode, allows you to have the shutter open up to 15 sec's. That, combined with a 12 sec self-timer should allow for quite a bit of light manipulation.
Spelunker Bob took us to Cedar Ridge the other night and showed us quite a few tricks.
Let's see if I can post an example!