AVL Trees

I'm currently learning for a computer science test and running into some problems concerning AVL trees--mainly, I just don't get it when it comes to rotations. Does anyone know some ressources on the web explaining AVL trees "for dummies?"

I just figured out (at least I hope so) the single rotation, but when it comes to multiple rotations, I'm completely and utterly clueless. Maybe I'm just overlooking something utterly obvious, so it'd be nice to have a step-by-step explanation of more complex multiple rotations.