I'm not sure if this is even worth an act they could of just combined it to act 3 or something. Well apparently the mad king is now (cool) with everyone and just wants to play games. He does a Simon says game he calls "Mad King says" in Lions Arch. It's pretty straight forward in what's needed. I'm not really sure if it takes crowd participation for a good reward or is it all on you. All I know is I didn't fail any commands and got silver.
For those who are not familiar with Simon says the game its simple. In this case its Mad King says "A random emotes". But only do it the mad king actually says "Mad King Says". If he does not say that then do nothing stand there. Failure to do that in anyway gets you a flat lining debuff that floors you. That's about it doesn't appear to be anything else for you to do in this act. I'm assuming you can still get very good loot from him after event completion.
For those of you who were late on act 3 unfortunately it's too late for that. Being that the mad king has already left his lair and is now tamed. However you can still do everything from act 1 and 2 so hurry and get those achievements. I'm glad everyone stuck around for the 4 parts and gave me love while doing them. You can be sure I'll do more with other events and other games.