South Downs Trailwalker 2013
The most gruelling endurance "walk" you'll ever want to do unless you're mad.
A major annual event run by the Gurkhas and Oxfam, with over £1.2m sponsorship raised being split between Gurhka Welfare Trust and Oxfam. Teams of 4 compete to finish a 100km course; the lead Gurkha team usually finishes in less than 10 hours. Note that the event continues overnight. About 2000 people total take part.