Calibre settings

Enter the following two expressions under Search & Replace in the conversion settings:

First expression
- Search Regular Expression: (<body.*>)(.|\n)*(<div class="main">)
- Replacement Text: \1\3
Second Expression
- Search Regular Expression: <hr.*><a name="kommentar">(.|\n)*(</body>)
- Replacement Text: </div>\2

This will cut out the left (contents) and right (ads) sides as well as the comment form. You will get a plain nice eBook.