Scratch

I've been tinkering with Scratch and Python lately, as I'm interested in re-learning programming.  Years ago I did a couple of programming courses in FORTRAN and Pascal, and only now I'm getting to understand a bit about OOP.  I've read about using classes and methods in Python, but I'm not sure I see how this analogy works in Scratch - which I understand is a OOP language itself.

Can anyone help explain OOP in Scratch to me, or link to some examples that incorporate objects, classes, etc?

thanks