Does anyone know of any full-scale internet april fools prank that's happening? I remember one year, they did a trailer for Zelda: The Ocarina of Time that got Zelda fans everywhere super excited (it was fake) but I didn't find out about it until like a year later.
It was IGN who made that trailer, wasn't it? Obviously, any prank that they pull would quickly become infamous among the gaming community, considering they're one of the biggest game sites around. Speaking as someone who actually fell for it until he looked at the date, it was pretty awesome. I don't know of any others that can match that one, but Wookieepedia (Star Wars Wikipedia) has switched all the text on the site to 3D. It's... extremely irritating. It's not so much a prank as rendering the entire site almost unusable; not the best strategy. They also had an image up on their homepage for a while claiming that LucasFilm had issued a cease and desist order due to all the copyrighted content they have.
World of Warcraft was touting an in-game hint system. I was quite disappointed when I saw that they weren't serious. I really hate April Fool's day. A few years ago, I was on a game-company forum and decided to try Tomb Raider because they were the other obsessive fanbase there. It was a complete accident of timing when I had to ask for help because I was stuck in the mansion for over two hours. (I was standing 2 inches to the right of where I needed to stand while opening the door.)
Found one. Youtube has a button next to the full screen button that turns everything into a 1911 silent film. I just watched dramatic fantasy anime with ragtime piano!