Simple table with caption:

\begin{table}[h]
\begin{center}
\begin{tabular}{rlcl}
Right
 & Left
 & Center
 & Default
\\
\hline
12
 & 12
 & 12
 & 12
\\
123
 & 123
 & 123
 & 123
\\
1
 & 1
 & 1
 & 1
\\
\end{tabular}
\end{center}
\caption{Demonstration of simple table syntax.}
\end{table}

Simple table without caption:

\begin{center}
\begin{tabular}{rlcl}
Right
 & Left
 & Center
 & Default
\\
\hline
12
 & 12
 & 12
 & 12
\\
123
 & 123
 & 123
 & 123
\\
1
 & 1
 & 1
 & 1
\\
\end{tabular}
\end{center}

Simple table indented two spaces:

\begin{table}[h]
\begin{center}
\begin{tabular}{rlcl}
Right
 & Left
 & Center
 & Default
\\
\hline
12
 & 12
 & 12
 & 12
\\
123
 & 123
 & 123
 & 123
\\
1
 & 1
 & 1
 & 1
\\
\end{tabular}
\end{center}
\caption{Demonstration of simple table syntax.}
\end{table}

Multiline table with caption:

\begin{table}[h]
\begin{center}
\begin{tabular}{>{\PBS\centering\hspace{0pt}}p{0.15\columnwidth}>{\PBS\raggedright\hspace{0pt}}p{0.14\columnwidth}>{\PBS\raggedleft\hspace{0pt}}p{0.16\columnwidth}>{\PBS\raggedright\hspace{0pt}}p{0.34\columnwidth}}
Centered Header
 & Left Aligned
 & Right Aligned
 & Default aligned
\\
\hline
First
 & row
 & 12.0
 & Example of a row that spans multiple lines.
\\
Second
 & row
 & 5.0
 & Here's another one. Note the blank line between rows.
\\
\end{tabular}
\end{center}
\caption{Here's the caption. It may span multiple lines.}
\end{table}

Multiline table without caption:

\begin{center}
\begin{tabular}{>{\PBS\centering\hspace{0pt}}p{0.15\columnwidth}>{\PBS\raggedright\hspace{0pt}}p{0.14\columnwidth}>{\PBS\raggedleft\hspace{0pt}}p{0.16\columnwidth}>{\PBS\raggedright\hspace{0pt}}p{0.34\columnwidth}}
Centered Header
 & Left Aligned
 & Right Aligned
 & Default aligned
\\
\hline
First
 & row
 & 12.0
 & Example of a row that spans multiple lines.
\\
Second
 & row
 & 5.0
 & Here's another one. Note the blank line between rows.
\\
\end{tabular}
\end{center}