The British company behind the Juicebar are billing it as "the world's slimmest emergency phone charger." The device looks about as big as a cardboard coaster, but apparently it is capable of powering up a phone for up to 480 minutes of standby, or around 60 minutes of talk time depending on the device. Full charge is reached in about an hour, but you are free to talk anytime during that period.
It also has a 5-year shelf life which the company has backed with a guarantee. Obviously, it makes more sense in the long term to have a rechargeable backup solution, but if you are caught in an emergency situation, dropping around US$6 on a Juicebar seems like a decent option. Juicebar is compatible with Nokia, Sony, Samsung, Motorola and Blackberry phones with an LG version coming soon—but, unfortunately, it is available in the UK only. [Juicebar via Gizmag]