aussietony
About 10 years ago the car maker MINI posted ads in Sydney newspapers detailing the new breakthrough technology VPL (Vertical Parking Locator) to be released with the new model, which would enable the car to be parked vertically. All the diagrams and technical descriptions made you think it was for real.
LetoHarkonnen
When I was 18 I told my Mom I was drafted to to go to combat in Beirut in the Marines....she was pissed.
msnuclearwinter
My best accidental prank (if you can even call it that) was when I broke my ankle. My parents called my work since I was outta town when I did it snowboarding. No one at my job believed them because it was April fools. So I guess they were fooled by thinking they weren't letting themselves be fooled.