Bell's law: If your cell phone battery is dead, it really doesn't matter how many bars you have.
Enter SideWinder, a small hand-crank charger that can give you enough juice to make or receive emergency calls.
The unit, half the size of your fist, has a small crank on the side. Hook it up to your cell phone using one of the five adapter tips. Turn the crank two revolutions per second for two minutes and you've got the power--the manufacturer claims at least six minutes of talk time and about 30 minutes of standby. Run out of power, crank it again.
The charger has a voltage regulator and a small LED light on the top that can provide a few minutes of low-level light after you disconnect the phone, perfect for finding your keys or tying up a boat after dark.
SideWinder comes in a carrying pouch and costs $25. It is available online from a number of travel and gadget stores. Power to the people.