My fascination with the state design pattern began when I was tinkering with UnrealScript back in 2002.  Epic Games (The developers of Unreal, Unreal Tournament, and Gears of War) created a scripting language that was syntactically similar to Java and had language-level support for objects with disntinct states.  It was very cool to be able to create a state for an object and override it in a child class with code like the following:

Attachments:

StateMachine.zip

[State Machine code and tests in C#]

572 Kb