Nigel Sampson will show you how to attach behaviors and how to manage triggers and actions.
For the most part we'll be adding or manipulating Silverlight / WPF Behaviors from Blend, but occasionally we'll need to manage these from code. Overall it's a pretty simple process. The main class we need to deal with is Microsoft.Expression.Interactivity.Interaction, from here we can retrieve the Behaviors and Triggers collections for a DependencyObject.