Sport: Rhythmic Gymnastics
Best Finish: No medal (2008 Beijing)
Alexandra won six golds (which is all of them) at the 2006 Commonwealth Games and three golds at the 2007 Pan Am Games. Although that did not guarantee her a podium spot in Beijing, she was undoubtedly on a roll. Unfortunately, that roll ended big-time with an 18th-place finish at the 2008 Summer Olympics. If it's any consolation, at least she beat out a million other women for a spot on this list.