Running through town in just boxers or less.
Eating a hot chilli (which I like anyway)
Going out (fancy dress) in a dress.
And loads of over random stuff really.
I've done those in the past.
Here's a dare -> hang off the side of a reefed small yacht in a Force 8-9 gale in shallow waters with a lee shore about 20 yards away, for about 2 or 3 hours.
I'm not that doing again..!
