Go on: amuse yourself at my expense. Unlikely as it may seem, I've signed up for the Westminster Challenge: a 400km trek across the Arctic wilderness, in temperatures as low as -40C, by husky dog sled. Just to make it more challenging, I'm going with a cross-party team of MPs, so I may well end up battling their analyses of macro-economic policy as well as the elements. Donating through this site is simple, fast and totally secure. It is also the most efficient way to sponsor me: the money will go to the Children's Society, Cancer Research and Crimestoppers - all excellent causes - and if you are a UK taxpayer, an extra 28% in tax will be added to your gift at no cost to you. Thanks in advance for your support, and if you need any more incentive, bear in mind you'll be able to follow my progress on my Guardian blog when we set off in February. Just think how forlorn I'll look traipsing across the tundra, and boost my spirits by signing up below. Thanks in advance, Tania