So, I was playing around a little in Ruby and noticed that |DateTime| is 
a subclass of |Date|, yet the method |today| is not defined for it.

I can certainly see how it doesn't make sense to have that method for 
that class, but I'm wondering why a Date isn't a DateTime?  I suppose 
then we'd be removing the time element, so we'd get the same problem... 
but it was just striking is all.