Along with a few equally stupid friends, I've signed up to the Rat Race Dirty Weekender, which takes place at Burghley House on May 11. 

The "race" is actually an endurance course of either 13 or 20 miles with obstacles to climb over or under, or swim through, or otherwise challenge my feeble limbs. We've signed up for the 20-mile version, for reasons that aren't yet clear to me.

I want to do this for two reasons. First, I want to challange myself. Secondly, I want to raise money and help out a colleague who has undergone something far worse than I will experience during the race.

I'll let her tell the story through her own website, http://www.10kforolly.co.uk/about/. All I need to add is that this is an incredibly worthwhile cause and I would be hugely grateful to anyone who wants to sponsor me. You'll get to help a little-known charity and, if you're lucky, I might even post photos of the state I find myself in after crossing the finish line.