a href="http://www.nytimes.com/2009/08/01/sports/01xgames.html?partner=rssnytemc=rss"img src="http://graphics8.nytimes.com/images/2009/08/01/sports/01xgames.75.jpg" border="0" height="75" width="75" hspace="4" align="left"/aAn X Games rookie who already has a reputation as the fastest rider on a motocross track, James Stewart has been cultivating an image as a free-spirited showman. More...