I have one of
these Maplin external batteries that I use a lot for charging my devices when out and about. Or I did. I've lost the MiniUSB adaptor. The device itself terminates in a MiniUSB so a MiniUSB to MiniUSB cable would do the trick. At a push, a standard USB to MiniUSB adaptor would also work.
Unless anyone else can think of something even better? I don't fancy paying £20 just to get the one adaptor - especially as I got the thing on special for £10 in the first place!