If homemade soap-on-a-rope isn't your thing, the folks over at Treehugger turned us on to this nifty little invention for reusing your miniscule soap slivers.
The Soap Bank works like a plain old soap dish for a new bar of soap, affixing to the wall with a suction cup. The innovation happens as the bar of soap diminishes -- when it finally gets small enough to slip through an opening in the bottom of the dish, it's caught by a net basket.
Rubbing the net basket with wet hands produces sufficient lather to get a few more handwashings out of the slivers of soap. Apparently the net basket attaches with magnets so one can remove it altogether for handwashing or cleaning.
The design is still a prototype so we'll have to wait to buy it, but it doesn't seem too hard to DIY in the meantime. The Soap Bank is by Designodoubt.