I'm not sure if you know this or not but you generally wrap table headings in a `<thead>` tag and the cell in a `<th>` tag. If you do this Bootstrap marks it up a little differently (I'm not sure if you did it this way on purpose though).

If you were unaware the markup would look like:

``` html
<table class="table table-striped table-bordered">
  <thead>
    <tr>
      <th>Date</th>
      <th>KMS</th>
    </tr>
  </thead>
  <tbody>
    <% @activities.each do |a| %>
      <tr>
        <td><%= a.date %></td>
        <td><%= a.value %></td>
      </tr>
    <% end %>
  </tbody>
</table
```