Remove All Widgets from Sidebar

You could add this function to your functions.php file.

add_filter( 'sidebars_widgets', 'disable_all_widgets' );

function disable_all_widgets( $sidebars_widgets ) {

  $sidebars_widgets = array( false );

  return $sidebars_widgets;
}

You could also use the WordPress conditional tags to disable widgets only on certain pages. For example; this would only disable widgets on the home page.

add_filter( 'sidebars_widgets', 'disable_all_widgets' );

function disable_all_widgets( $sidebars_widgets ) {

    if ( is_home() )
        $sidebars_widgets = array( false );

    return $sidebars_widgets;
}