And speaking of oscillations, here's a nice video of the Belousov-Zhabotinsky reaction in a petri dish:
(The video info for the above also has a nice description of waveforms in the brain which is worth reading.) You can see someone setting up the reaction (ie pouring some chemicals together and stirring, really) here.
The BZ reaction is an example of a chemical oscillator, a system which instead of arriving at a steady state transitions between two different chemical states (which two states have two different colors, whence the waves above). Boris Belousov discovered it in the 1950's when he happened to mix together potassium bromate, cerium(IV) sulfate, propanedioic acid and citric acid in dilute sulfuric acid (hell, why not?); he made two attempts to publish his findings, but was rejected from peer-reviewed journals because he couldn't explain why the oscillations occurred.