I want to learn MVC "architecture pattern" but I don't want to jump into a framework like Rails or Django just yet. I want to understand the concept first and write some simple code in my currently familiar environment, which happens to be PHP/HTML/CSS/MySQL. I don't necessarily need a tutorial that is based on PHP, as I do understand a lot of different languages. And I don't want to have to install any frameworks or APIs or libraries. I just want to learn how to think in MVC and apply it to my projects. Any suggestions?
Almost every framework does MVC differently, so you might end up getting even more confused. The general principles of MVC are very simple: "Model is state; view reacts to model; controller reacts to view; controller changes model". The model, view and controller are concepts - they are whatever you feel them to be. Classes, bunches of classes, instances of classes with XML configuration files, you name it.
I actually think that about covers the basic principles. Without a framework, you'd not get much further. What matters is how a particular framework defines model, view and controller and their interactions.