Andy Ihnatko's pick on MacBreak Weekly episode 376 is the MicroPro from Lite Panels. This is a portable version of the professional LED light panels that you may have seen studios use for video and photography.
MicroPro runs off a variety of AC voltages, and lasts a long time on a set of six AA batteries. While it's capable of producing an ample amount of light, it can be adjusted to hit just the level you may need. Andy's found this to be very useful for when he's away from a studio environment, and it's even made pictures taken with his cell phone look better.
MicroPro isn't cheap -- It costs $350. But if you're in a pinch and need the extra light on the go, this is the perfect solution.
For more on MicroPro from Lite Panels, check out MacBreak Weekly episode 376.