We can't work out if this one smacks of clever marketing or just a bit of desperation. We'll go with the former.
Basically, if you get approached by a stranger in the street offering a bit of spanking in return for £20, don't automatically assume they're a pervert and run off screaming. Because you may be in line for a bit of cash.
It's all part of the campaign by Microsoft to push Windows Phone 7 and get it into the public consciousness. They've been doing it in the US for a little while now (the term used over that side of the Atlantic is 'smoking' and people are challenged to do things with their Android handsets or iPhones that Windows phones can apparently do faster. If you manage to beat (or spank) the Windows handset, you win the dosh. Simples.
Basically, the Nokia Lumia 800 has sold well - but not as well as Nokia had hoped. And this is a way of raising awareness by grabbing members of the public in the street and extolling the virtues of mobile land's new OS. Because, only do you get your £20 note, but also a £100 cash back deal on the Lumia 800 at Phones 4U (providing you sign up to a contract of course.)
Check out www.wpdaresyou.co.uk to find out where you can take part.