hey Roberto, whatever happend to the idea of not knowing what to model next day? or did i miss that in your rules!
also, i thought you would provide a specific list of things to model. this seems too open ended and looks more like a workshop(which is very usefull too) rather than a challenge. everyone is gonna model something different. since you took the idea from a workshop this is expected, but to make it into a challenge i believe there should be a goal; i.e. a goal list of models from day 1 to day 30 and we only know what to model for the next day.
the way it is now, people will model some of the harder thing for more than a day and then just show it in 1 day. the point of the challenge becomes mute here.