"The Puffer"; it's an endearing abbreviation, it makes it seem somehow cuddly. Don't be fooled!
In the UK it's the type of event that we might best describe as "character building".
Fundamentally it's a 24 hour mountain bike race; nothing unusual in that, there are plenty of them on the calendar, there's even a World Championships. It has Solo, Pairs, Quads, and Team of Ten categories. The Solo's, quite rightly, attract the most attention; and the places sell out in less than five minutes every year!
It is probably the hardest 24 hour race going. Any self respecting endurance racer should have this on their palmares.
It's the most fun you can have in January with your (many layers) of clothes on!