In April 1975, Martin Gardner's column in _Scientific American_ listed six "sensational discoveries of 1974", beginning with a full-page illustration of a map that required five colors, and working its way up to a motor that would run on psi power if placed on a Bible or a copy of I Ching. Thousands of readers (all, one may presume, scientifically literate) either confirmed the results or took an absurd amount of trouble to disprove them.
An exquisite *natural* April Fool trick was played on Boston in (IIRC) 1997. After an almost snowless winter, the city got about a foot and a half of snow on the night of 31 March - 1 April.
--- Joe Fineman firstname.lastname@example.org
||: You're never too old to do something stupid. :||