Q:

How to force a \colorbox to be \pagewidth

I am wanting to make a band of color that stretches across the entire page that will have contact information inside of it.  I am attempting this using the color package, and \colorbox.  I can not seem to get the band of color to begin at the left edge of the page.  Is this possible with this package? 
Here is an example of what I have tried:
\documentclass[letterpaper, 12pt]{scrartcl}
\usepackage{color}

\begin{document}

\colorbox{cyan}{ \parbox{8.5in}{test} }

\end{document}

A:

You have to move the box left by \oddsidemargin+1in, besides taking into account \fboxsep. 
\documentclass[letterpaper, 12pt]{scrartcl}
\usepackage{color}
\usepackage{lipsum}

\begin{document}

\noindent\makebox[\textwidth][l]{%
  \hspace{-\dimexpr\oddsidemargin+1in}%
  \colorbox{cyan}{%
    \parbox{\dimexpr\paperwidth-2\fboxsep}{\lipsum[3]}%
  }%
}

\end{document}

