The athletics events get under way at London's Olympic Stadium later, ensuring the Olympic Park's busiest day since the Games opened a week ago.More than 200,000 people will be at the park, prompting warnings for those not attending the Games to avoid the area.Great Britain have hopes of further gold medals during the day, including in rowing, track cycling and swimming.Team GB have risen to fifth in the overall medal table with five golds after three were secured on Thursday.Among the gold medallists on day six were track cyclist Sir Chris Hoy. His victory, with Philip Hindes and Jason Kenny in the team sprint, represented his fifth Olympic title and equalled rower Sir Steve Redgrave's record British, Olympic gold medal haul.Earlier in the Velodrome there had been disappointment as fellow cyclists Victoria Pendleton and Jess Varnish were disqualified from the women's team sprint for an infringement, after having appeared to have qualified for a final against China.Pendleton gets a chance to make amends later when she appears in the keirin - one of a number of British competitors who could secure medals.Hopes are high for rowers Katherine Grainger, who has three silvers from three previous Olympics, and Anna Watkins in the double sculls, swimmer Rebecca Adlington, who defends her 800m freestyle title, and the men's track cycling pursuit team.Highly fancied heptathlete Jessica Ennis also gets her campaign under way at the Olympic Stadium, in the 100m hurdles, the high jump, the shot put and the 200m.Other British athletes in action on Friday will include world champion Dai Greene in the men's 400m hurdles heats and defending Olympic champion Christine Ohuruogu in the women's 400m.