Flip dots are one of the most iconic analogue displays. They contain a small metal disc and two magnetic coils. By charging the coils you can flip the disc back and forth – revealing different colours. Put lots of these together and you can large scale kinetic displays like those seen in public spaces like train stations. As well as looking (and sounding) great, one of the benefits of these kinds of displays is that once set, the display can show information indefinitely without using power.
I got mine from flipdots.com. When I find out ways of driving them efficiently I’ll post more.