Soon I shall spend the day in the hallowed portals of the Foreign & Commonwealth Office in Whitehall. On the fine marble floor of the Durbar Court, only white wine can be drunk at receptions so nasty stains are avoided. Shall I be shadowing mandarins to enable me to acquire the diplomatic skills I have so long coveted?
No, and I won't be anywhere near the elegant bits of the FCO, but in the rather ordinary staff canteen, Macmillan's recovery centre for its huge team in the Flora London Marathon. During the day hundreds of runners will come through the centre - each one applauded in, offered food and fluids, massage for screaming muscles and first aid for bleeding feet.
My job is to thank them personally and chat, if they want, about their time, exhaustion, going 'through the wall' and thinking of dropping out, the boost of hearing themselves cheered by name all round the endless route.
I'm interested to know why they do it. Some are regular runners who thought we offered a good support package. Many more are one-off runners who will never do it again. Behind the elation, nearly everybody has some direct connection with cancer, often very recent and painful, sometimes more distant, but no less motivating to do something to alleviate the suffering of people such as those they care about.
There will be high-profile people among our runners, but the marathon is a great leveller. Success in the boardroom is no guide to achievement over 26.2 miles, and fame doesn't prevent blisters, cramp or falling over.
One of my own small team is training for the event. I don't know where she finds the commitment to tackle the dark morning runs and the weekend training that brings her back to the office exhilarated but exhausted.
The London marathon remains the biggest single one-day fundraising event in the UK, with more than £200m raised since 1981. For some charities it is their major annual source of income. It also illustrates what happens when charities support their supporters in turn, responding to their needs with training days, online sponsorship pages, fundraising packs and pasta parties. But in the end, for those who run for charity, I hear the cause is the overriding motivator. It's further confirmation, after the tsunami and Red Nose Day, that charity is alive in the UK and pounding the pavements near you.