Sorry I'm with Fury on this one. It's not much of a headache because turning off javascript fixes the problem pretty quickly. But that kind of defeats the purpose of the joke, doesn't it? Ideally an April's fools joke would be some kind of funny prank that is omnipresent during the day while not making the boards unusable. If it forces people to turn off javascript within 2 seconds of seeing it, then it's not much of a joke since it'll be gone after a quick tweak in the browser people were forced on. A good one would have at least a small degree of subtlety in it too - this one is just in-your-face, ocular nerve rape without much of a punchline apart from the "lol you can't see anything" factor.
Again, don't much care. Will just reenable javascript on HLP tomorrow. Doesn't make me laugh but doesn't manage to annoy much either.