A whole tone scale is very useful to know about. It is often used to produce a dreamy, fantasy-like character to music and is used in film and television sound tracks to indicate moving from one dimension to another - a flashback or dream sequence, for example.
A whole tone scale is really easy to build as well. Instead of a combination of semitone and tone steps, like the major and minor scales, this scale is just a series of tones. This means that actually there are only two different versions of the whole tone scale, making it very easy to remember.