Mood Ring + Brainstorm = Moodstream

You've got to check out Moodstream from Getty Images.  From the site:

Moodstream is a powerful brainstorming tool designed to help take you in inspiring, unexpected directions. Whether you want images, footage or audio, or just need a stream of fresh ideas, tweak the Moodstream sliders to bring a while new creative palette straight to you.

It is really hard to describe, but think of a constantly changing mixture of pictures, video and music that can be customized with sliders in the following ways: happy to sad, calm to lively, humorous to serious, nostalgic to contemporary and warm to cool.  Very neat stuff.  And of course you can purchase the images if you see something you like.