\frame[containsverbatim]{ \frametitle{Summary}
  \begin{itemize}
    \item Cactus is a powerful framework for developing portable applications,
          particularly suited to large collaboration.
    \item Cactus is currently used by many groups around the world, in several
          fields.
    \item For more information: \verb|http://www.cactuscode.org|,
      Users' guide (available online, also distributed with Cactus)
  \end{itemize}
}