This bloke is wearing a GCC backpack - which stands for Global Corporate Challenge. I did it a few years ago, before I started cycling seriously. Very good idea - I suggest you give it a go this year if possible.
Some fixed gear cyclists take the minimal approach very seriously. This bloke was so serious about attaching nothing to his bike that instead of carrying his water bottle in a water bottle holder, he had it in his back pocket. Same goes for the pump. If you ask me, that's taking things a bit far.