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?
![Young spectators enjoying the St Luke's It's a Knockout Day held at the HSBC Sports ground in Dore - July 2009](https://www.thestar.co.uk/webimg/b25lY21zOjU5YTEzNDM0LTViZWYtNDk5ZC1iOTc4LWJhYWJiM2FlMDFlOToxYzI0MDRmZi0yOWY0LTRjZGUtYjZkZi02MmUyNjk1ZTNlMDU=.jpg?crop=3:2&width=640)
5. Having fun
Young spectators enjoying the St Luke's It's a Knockout Day held at the HSBC Sports ground in Dore - July 2009 Photo: Sheffield Newspapers
![Pictured at Graves Park, Sheffield, where the It's a Knockout Challenge in aid of the Children Today charity was held. Seen are competitors during the games - July 2008](https://www.thestar.co.uk/webimg/b25lY21zOmIwNTViNDEyLWQzYjAtNDNkNy1hZTAyLWZmMWU1MjhkMDk4ZjpmOTQ5NmFkMC0yZDI1LTRlZWEtOGI1ZS0wOTQ1YjQ3OTllYWQ=.jpg?crop=3:2&width=640)
6. Water fun
Pictured at Graves Park, Sheffield, where the It's a Knockout Challenge in aid of the Children Today charity was held. Seen are competitors during the games - July 2008 Photo: Michael Waistell
![The St Luke's It's a Knockout Day held at the HSBC Sports ground in Dore - July 2009](https://www.thestar.co.uk/webimg/b25lY21zOmVmY2FjNGM5LWQ3MGItNDk2Yy1iYjAxLThmYzc2M2I5ODU1MDowMjU1MWZhZS1jYmI0LTQwMGYtOGUyOC1hZjRlNTBkZDcxMzE=.jpg?crop=3:2&width=640)
7. Trip up the giants
The St Luke's It's a Knockout Day held at the HSBC Sports ground in Dore - July 2009 Photo: Sheffield Newspapers
![Pictured at Totley Primary school, where the St Luke's It's a Knockout competition was held - July 2008](https://www.thestar.co.uk/webimg/b25lY21zOjljZTVlNGY1LTkzYzEtNDExYy1iOTczLTg2OGFiYjYxOGNkODoxNzViNjBjNy02MGI4LTQ0OGMtODQxNS04ODRmMGU4ZjYwZDU=.jpg?crop=3:2&width=640)
8. Totley Knockout
Pictured at Totley Primary school, where the St Luke's It's a Knockout competition was held - July 2008 Photo: Michael Waistell