How to show active section in table of contents in a beamer presentation?

[jeromyanglim]

This tutorial shows how to do it: http://webapp13171708132.wordpress.com/2011/04/09/latex-beamer-current-section/

\begin{frame}{Table of Content}
\tableofcontents[currentsection]
\end{frame}

Or for a more automated approach see: http://heather.cs.ucdavis.edu/~matloff/beamer.html

\AtBeginSection[]
{
   \begin{frame}
       \frametitle{Outline}
       \tableofcontents[currentsection]
   \end{frame}
}