Dave has made an excellent video tutorial on building and using Dickson voltage doubler made if diodes and capacitors. This appears to be a cheap and easy way of rising voltage for low power applications.
For instance, if you microcontroller circuit is powered from the 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 the tutorial, there are real measurements made with different loads attached. [source]