So, another Sport Relief adventure has begun.
I've been privileged to have helped a host of individuals push their physical and mental boundaries to help raise money for the charity over the past decade and there have been some memorable moments.
David Walliams' two extraordinary swims of the channel and the Thames, John Bishop's utterly brutal week of hell, climbing Mount Kilimanjaro, traversing a Kenyan desert, these have all been astounding achievements.
After the first day of the latest BT Challenge which sees Davina McCall attempting to travel the 500 miles from Edinburgh to London under her own steam, and my suspicions that this will be one of the toughest yet have been proved to be correct.
When you are faced, as Davina is, with scaling England's highest peak, swimming a lake with waters that are hovering above freezing point and putting in a marathon to finish, its tempting to see the cycle legs as relative respite.
And that would be a big mistake.
When you consider that Tour de France cyclists average 104miles a day it begins to put what Davina achieved on Saturday into perspective - a 130mile ride through the Scottish lowlands and Borders in February is looked to be hugely demanding by anyone's standards.
And so it proved. The weather was nothing short of atrocious. Icy gusts of up to 50mph threatened to de-saddle Davina and as the rain turned to persistent sleet the cold set in and stayed in.
Davina coped admirably and after a very dark spell in the freezing late morning she recovered well to complete the huge Edinburgh to Keswick leg.
But as is the way on these Sport Relief challenges it's the attritional nature of them that makes them so extraordinary.
To have completed a cycle like that and have to scale Scafell Pike the day after is what makes this special. To then have to swim the width of Lake Windermere the day after that followed by another huge cycle and a full marathon to finish is what makes them truly memorable.
The journey has well and truly begun alright!