Joker "semi" funny

So, now that we're only a year away from The Dark Knight, the news is starting to come fast and furious. And with the wonders that are the internets and ebays, comes Youtube. And Youtube my friend, you have brought us fantastic wonders of videos, like this one, which shows Joker's fancy new semi in action. Check it out if you want a slight spoiler about the movie. I haven't watched it, but why should I deprive those that hate surprises?