Here's 3 examples of playing with color, reference lines and parameters that I presented at the Tableau Customer Conference 2013 along with a bunch of terribly clever people. The other presenters workbooks can be obtained here
TCC13 Rapid Fire Tips and Tricks.
I've updated the workbook to make it easier to follow. Download the workbook to save as future reference. Enjoy!
The detailed instructions to produce example #3 can be found in a previous post
Replicating a New York Times d3js chart.