\usepackage {color}
\setlength{\fboxrule}{6pt}%
\setlength{\fboxsep}{10pt}%
\colorbox{yellow}{Fun with color}\qquad
\fcolorbox{red}{yellow}{Fun with color}
\par\bigskip\par
\setlength{\fboxrule}{1pt}%
\colorbox{green}{Fun with color}\qquad
\fcolorbox{red}{green}{Fun with color}