This seems to be already asked before:
This might help:
Twitter Bootstrap Use collapse.js on table cells [Almost Done]
UPDATE:
Your fiddle wasn't loading jQuery, so anything worked.
<table class="table table-hover">
<thead>
<tr>
<th></th>
<th></th>
<th></th>
</tr>
</thead>
<tbody>
<tr data-toggle="collapse" data-target="#accordion" class="clickable">
<td>Some Stuff</td>
<td>Some more stuff</td>
<td>And some more</td>
</tr>
<tr>
<td colspan="3">
<div id="accordion" class="collapse">Hidden by default</div>
</td>
</tr>
</tbody>
</table>
Try this one: http://jsfiddle.net/Nb7wy/2/
I also added colspan='2'
to the details row. But it's essentially your fiddle with jQuery loaded (in frameworks in the left column)