I spotted them for the first time during the Peltier lamp project: these cute little USB LED spotlights from a certain Swedish retailer that we don't need to name. Not that I knew of an immediate application for these, but it is one of those things that continue to stick around in my head. Some time later, in one of the local discount stores, I came across a Li-ion powerbank that had modest dimensions. These are actually intended for an emergency charge infusion of your tablet or mobile phone when you're away from home or when you have forgotten to charge them.