This morning I built a small toy called posical, which models August Comte's Positivist Calendar in python. It seems to be a sort of spiritual little brother to abba. Next I'll want to make it understand timedeltas so you can do date math. But finally it seems like it would be fun to generalize it into an all-purpose tool for constructing alternate calendars; god knows there are enough of them floating around and it'd be fun to make a general model.