Photojojo has a guide to taking portraits at night, and while some of them you might already know (bump up your ISO, use a tripod, etc.) They also offer ideas to get more creative, such as this one:
_Hold Sort of Still:
* Set the camera up on a tripod.
* Have the person pose before pressing the shutter button.
* As soon as the flash fires, have the person change position and freeze for the rest of the exposure.
Try giving the person two heads, or four arms, or whatever else you can think of. Create your own sideshow!
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