Dave have made a nice video tutorial on building and using Dickson voltage doubler made if diodes and capacitors. This appears to be cheap and easy way of rising voltage for low power applications.
For instance if you microcontroller circuit is powered from 3V power supply and you want to attach 5V LCD it may be useful to consider a voltage double to increase supply voltage instead of designing additional power supply branch. In tutorial there are real measurements made with different loads attached. [source]