BBC NEWS | UK | Magazine | The art of fooling around
I was a little young to have noticed the BBC spaghetti hoax, but one of the best April Fool hoaxes I've seen was, if memory serves, an NBC News piece by John Chancelor 30 years or so ago. It was a report on the state of the pickle crop, complete with footage of the pickle orchard, workers and all.
Scientific American has had some memorable April Fool pieces, too. One I remember was about how you could increase the mass of a block of gold by simply cutting it up in a certain way, and then put it back together again in a different form. The article started out by showing how you could increase the area of a piece of paper by cutting it into a certain pattern and then put the pieces back together differently. They then extrapolated to three dimensions to increase the volume of the block of gold.
I'm happy to say I didn't fall for it, but I didn't spot the trick right away, either.
Another Scientific American April Fool piece was about a method for connecting one end of a wire to a stationary base, and the other end to a rotating platform, in such a way that the wire would not be twisted when the rotating platform rotated. The piece was complete with detailed drawings of a lab device with a conduit passing through the axis of the rotating platform with a geared mechanism to change the relationship of the wire conduit to the rotating platform as it rotated. Something like that. This may be my favorite April Fool joke of all time.