I taped the LED on all of the mouses of my co-workers. then unplugged the mouse. That way if they think they solved on solution, they will have to find out the other problem!. I also want to make this bizarre april fool's joke (I believe I just came up with on my own) somehow work: I just came back from the doctor because I had bumps on my dick. He told me "good news, your test came back positive for herpes!" I asked if that was an april fools joke, he said "yes, i lied, having herpes isn't good news"
I think it was last year or the year before, goggle made it so all of their searches resulted in a Rick-Roll. I'd say that's a pretty great April Fools joke right there.
One year, before my wife was a citizen, I told her we'd just received a letter from the INS and she was going to be deported. (I was actually holding a copy of the gas bill and just made up the text as I went.) I could only keep the joke going for about a minute because of the look of panic on her face. That is my all-time most evil April Fools joke.
Another year I had a glass of wine, and then went and did some carpentry. I made it pretty obvious I was a little tipsier than I really was. I came running in screaming, huddled over and swearing because I'd cut off my thumb. She was dialing 911 before I said, "Oh, never mind. I guess I cut the wood instead." The look on her face was priceless. After a decade of marriage, I don't even try anymore. She looks at the calendar around March 20th and reminds me every other day or so she knows it's coming.
I think serious places like hospitals should just ban april fool's jokes. "Good news, the cancer has completely cleared up and you're going to live!" "really?" "nope, April Fools!" Or any sort of ground breaking scientific discovery. "Hey guy's I finally found the cure for AIDS!" "Dan, that is a terrible april fool's joke!" "No I'm serious I found the cure!" "yeah, right!"
I heard people printed up a bunch of "Coming Soon: IN-N-OUT" signs and plastered them all over construction sites and empty storefronts in NYC.