Nike+

I bought the Nike+ kit the other week, it's a sensor and a receptor that you connect to the iPod nano. It gives you all kinds of stupid but fun statistics. Then you can upload that via iTunes to get cool graphs like the one above :-). Now, inside the nike+ site one can set up challenges for other people, anybody else here using this? I think I can manage to get Tomas to sign up for it :-) The more the merrier.