Notes not in the chromatic scale?

[Capt. Ridley's Shooting Party]

I was eading through Dansm's music theory website (http://www.people.fas.harvard.edu/~d...rds/theory.htm), and came across this paragraph:

The figure below shows the twelve notes of the chromatic scale. These are the only notes used in Western music. Notes such as D# and Eb represent the same pitch and are called enharmonic equivalents. Different enharmonic equivalents are used in different scales; the sharp is used for sharp keys (e.g. F# major), and the flat is used in flat keys (Ab major).

Surely this implies that non-western music has notes which do not make up the western chromatic scale.

What are these notes, and what styles of music, regions and instruments are they used in?