I want to have one table header be centered over two table columns side by side. Is this possible?
<th colspan="2">. This .</th>
To extrapolate a bit...
<table>
<thead>
<tr>
<th>Single Column</th>
<th colspan="2">Double Column</th>
</tr>
</thead>
<tbody>
<tr>
<td>Column One</td>
<td>Column Two</td>
<td>Column Three</td>
</tr>
</tbody>
</table>
That should give you enough to work from.