Here's how to do a table with rounded corners in CSS3 -- Updated: Fixed bug where bottom left corner wouldn't be rounded with only one TD in last TR

rounded_corners_table.sass

@import compass/reset
@import compass/css3/border-radius

table
    border: none
    border-collapse: separate
    th, td
        padding: 5px
    thead
        background-color: #f2f6fa
        th
            border: 1px solid #ccc
            border-left: none
            &:first-child
                border-left: 1px solid #ccc
                @include border-top-left-radius(5px)
            &:last-child
                border-right: 1px solid #ccc
                @include border-top-right-radius(5px)
    tbody
        tr
            td
                border-right: 1px solid #ccc
                border-bottom: 1px solid #ccc
                &:first-child
                    border-left: 1px solid #ccc
            &:last-child
                td
                    &:first-child
                        @include border-bottom-left-radius(5px)
                    &:last-child
                        @include border-bottom-right-radius(5px)

sample_table.html

<table>
  <thead>
    <tr>
      <th>name</th>
      <th>email</th>
    </tr>    
  </thead>
  <tbody>
    <tr>
      <td>john</td>
      <td>john@domain.com</td>
    </tr>
    <tr>
      <td>jane</td>
      <td>jane@domain.com</td>
    </tr>
  </tbody>
</table>