Plain sample table

gistfile1.tex

\begin{table}
  \caption{Table caption}
  \centering
  \begin{tabular}{l | r r | r r}
          & \multicolumn{2}{>{c|}{A} & \multicolumn{2}{c}{B} \\
      Foo & 1 & 2                    & 1 & 2\\
      \hline
      1   & a & b                    & c & d \\
      \hline
  \end{tabular}
\end{table}