Easiest thing to do would be to hook up the dome light from your car to that gel cell in an emergency...free, and easy.
Hooking anything else up would require some form of voltage converter...an LED would require a zener diode, and a current limiting resistor, but would practically run forever off of a typical 12V 7.2 AH gel-cell...
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Member of the toughest, meanest, deadliest, most unrelenting -- and ablest -- form of life in this section of space, a critter that can be killed but can't be tamed. --Robert A. Heinlein