\documentclass{beamer}

\usetheme{Darmstadt}

\begin{document}

\begin{frame}
  \frametitle{FrameTitle}
  \begin{columns}[onlytextwidth]

    %% this column contains the main content
    \begin{column}{\textwidth}
      \begin{block}{Title1}
        \begin{itemize}
        \item item1
        \item item2
        \item item3
        \item item4
        \item item5
        \item item6
        \item item7
        \end{itemize}
      \end{block}
    \end{column}

    %% this column contains the content next 
    %% to the previous one. Therfore we have to
    %% move all the content to the left 
    \begin{column}{\textwidth}
      %% move block over to the main column
      \hspace{-1.01\textwidth} 
      \begin{minipage}{\textwidth}
        \begin{exampleblock}{Title2}<2->
          TODO 
        \end{exampleblock}
      \end{minipage}
    \end{column}
    
    %% How about a rotated box
    \begin{column}{\textwidth}
      %% move block over to the main column
      \hspace{-1.9\textwidth}  %% move block to the
      \begin{minipage}{.9\textwidth}
        \rotatebox{15} {
          \begin{minipage}{.9\textwidth}
            \begin{alertblock}{Title2}<3->
              {\huge IMPORTANT } 
            \end{alertblock}
          \end{minipage}
          }
      \end{minipage}
    \end{column}

  \end{columns}
\end{frame}

\end{document}
