Please read the following table in HTML format from a webpage and then answer the question in detail according to the table. Each table cell is defined by a <td> and a </td> tag. Each table row starts with a <tr> and ends with a </tr> tag. 'rowspan=m' and 'colspan=n' represents a cell spaning over 'm' rows and 'n' columns.

Webpage title:
List of awards and nominations received by Slipknot
Table title:
Grammy Awards
Table:
<table id='hittask' contenteditable='False'>
<tr> <th colspan=1 rowspan=1 > Year </th><th colspan=1 rowspan=1 > Nominee / work </th><th colspan=1 rowspan=1 > Award </th><th colspan=1 rowspan=1 > Result </th></tr>
<tr> <td colspan=1 rowspan=1 > 2001 </td><td colspan=1 rowspan=1 > "Wait and Bleed" </td><td colspan=1 rowspan=3 > Best Metal Performance </td><td colspan=1 rowspan=1 > Nominated </td></tr>
<tr> <td colspan=1 rowspan=1 > 2002 </td><td colspan=1 rowspan=1 > "Left Behind" </td><td colspan=1 rowspan=1 > Nominated </td></tr>
<tr> <td colspan=1 rowspan=1 > 2003 </td><td colspan=1 rowspan=1 > "My Plague" </td><td colspan=1 rowspan=1 > Nominated </td></tr>
<tr> <td colspan=1 rowspan=2 > 2005 </td><td colspan=1 rowspan=1 > "Duality" </td><td colspan=1 rowspan=1 > Best Hard Rock Performance </td><td colspan=1 rowspan=1 > Nominated </td></tr>
<tr> <td colspan=1 rowspan=1 > "Vermilion" </td><td class="highlighted"  colspan=1 rowspan=5 > Best Metal Performance </td><td colspan=1 rowspan=1 > Nominated </td></tr>
<tr> <td class="highlighted"  colspan=1 rowspan=1 > 2006 </td><td class="highlighted"  colspan=1 rowspan=1 > "Before I Forget" </td><td class="highlighted"  colspan=1 rowspan=1 > Won </td></tr>
<tr> <td colspan=1 rowspan=1 > 2009 </td><td colspan=1 rowspan=1 > "Psychosocial" </td><td colspan=1 rowspan=1 > Nominated </td></tr>
<tr> <td colspan=1 rowspan=1 > 2015 </td><td colspan=1 rowspan=1 > "The Negative One" </td><td colspan=1 rowspan=1 > Nominated </td></tr>
<tr> <td colspan=1 rowspan=2 > 2016 </td><td colspan=1 rowspan=1 > "Custer" </td><td colspan=1 rowspan=1 > Nominated </td></tr>
<tr> <td colspan=1 rowspan=1 > .5: The Gray Chapter </td><td colspan=1 rowspan=1 > Best Rock Album </td><td colspan=1 rowspan=1 > Nominated </td></tr>
</table>
Question:
What song did Slipknot receive the Grammy for Best Metal Performance for in 2006? 
Answer:
In 2006, "Before I Forget " won a Grammy Award for Best Metal Performance.