<DIV>Beware: these puzzles are so hard, they may scorch your brain! Of course, some people like to get burned once in a while, especially by brilliantly executed crosswords with devilishly difficult clues. If you enjoy the Friday and Saturday offerings from sources like the <I>New York Times</I>, you'll love these tricky crosswords, which come with explanations for the toughest clues along with the answer grids. Solve with a pen at your own risk!</div>