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

Table without column headers:

\begin{center}
\begin{tabular}{rlcr}
12 & 12 & 12 & 12\\
123 & 123 & 123 & 123\\
1 & 1 & 1 & 1\\
\end{tabular}
\end{center}

Multiline table without column headers:

\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}}
\parbox{0.15\columnwidth}{First
} & \parbox{0.14\columnwidth}{row
} & \parbox{0.16\columnwidth}{12.0
} & \parbox{0.34\columnwidth}{Example of a row that spans multiple lines.
}\\
\parbox{0.15\columnwidth}{Second
} & \parbox{0.14\columnwidth}{row
} & \parbox{0.16\columnwidth}{5.0
} & \parbox{0.34\columnwidth}{Here's another one. Note the blank line between
rows.
}\\
\end{tabular}
\end{center}