We did it last year: a 20km night hike around London to raise money for Maggie's brilliant cancer caring centres.
Yes, it's a long walk; yes, it will take you all night; and yes you will - perversely? - enjoy it
This year again the hike coincides with Open House weekend and notable London buildings will be open to night hikers as rest and snoop stops although the former becomes much more important as the route wears on. Leadenhall Market, City Hall, Southbank Centre, Royal Geographical Society, RIBA, Horse Guards and 20 Gresham Street are already signed up. The best stop of the night is Maggie's in Hammersmith. If your feet can bear it have a nose around the lovely, welcoming, sweet smelling, orange haven!
For the first time this year 10- and 20-mile hikers will be able to walk together so if you've got mates who can't manage the long haul, they can start with you and wave a cheery goodnight halfway round.
Register online now. The Night Hike takes place on Friday 16 September 2011.
Not convinced? Watch the video of last year's hike. It's good, except we're a bit miffed the 10 milers got a glass of fizz at Bloomberg - not on the 20m route! Also note, the singers at RIBA made us cry. We were tired.