Last night I wanted to play with the flash on my camera in conjunction with long exposures. So out came the tripod and headlamp, into my office I went, and off went the lights. I'm sure the neighbors thought it was Watergate all over again with the lights flashing on wall and window alike.
Now just about every point and shoot camera comes with a 'Slow Synchro' flash option these days, which is the same thing as first curtain flash. On most high-end cameras you also have the option for second curtain, which can be advantageous for getting different effects. Basically, first curtain fires the flash, and then leaves the shutter open for however long you tell it to. Second curtain leaves the shutter open (for however long) THEN fires the flash at the end, freezing the action at the end of the exposure.
Now if you mix this concept with a long shutter speed, and an external light source you can get some interesting effects, like movement and still-life in the same image.
I ended up having the most success with the second-curtain option. Example (forgive the office crap. It was a very impromptu experiment):
Second curtain also allows you to do some still light writing, as long as you can get out of the shot before the flash fires. Example:
And by utilizing the leaked light from the headlamp you can even include the artist-at-work in a shot:
Not too shabby for 30 minutes of messing around. :) Of course DaNece thought I was a crazy mofo until she saw the results.