The 2006SE ZCTA map has undergone an upgrade to show new imagery and more details. The colors have been switched from 100 random colors to just 8 pastels, which is more in line with standard mapping practices. The algorithm to compute colors is not perfect, a perfect one would have only used 5 colors, but 8 is pretty good. If anyone is interested in this algorithm, one I developed myself, I would be happy to share it. At some point it may be published as a Google Code article.