Based on the popular TV programme, fun obstacle courses were commonplace at charity and community events back in the day.
This gallery of colourful photos from our archives looks back at some knockout madness in the noughties – can you spot yourself or anyone you know?
![Some of the competitors getting very wet during the It's a Knockout Challenge in aid of the Children Today charity at Graves Park - July 2008](https://www.thestar.co.uk/webimg/b25lY21zOmQyZjFmZWNiLWM2MTAtNDBiOS04MTc3LTkzOWQxZjEzNTAzZjpiNTVjMDVhNC02NjBjLTQ3N2QtYmI0NC0wZDM5N2M4YzQwMzU=.jpg?crop=3:2&width=640)
9. All in a good cause
Some of the competitors getting very wet during the It's a Knockout Challenge in aid of the Children Today charity at Graves Park - July 2008 Photo: Michael Waistell
3 / 3