PHP = "PHP Hypertext Preprocessor"
Yes, a recursive-acronym as described here: http://www.tuxedo.org/~esr/jargon/html/entry/recursive-acronym.html
And isn't it just so witty that since it's a PREprocessor there is a 'P' in the front of the H(ypertext)? Doesn't it also just look like a PHP tag in some simplistic way (the P's being the <? and ?> respectivly surrounding the 'H'?
PHP could stand for Personal Home Page, it could also stand for Personal Handy Phone or Partial Hospitalization Program ... I just think the recursive acronym is much more likely. A million guesses, perhaps some day the creators of PHP will settle this battle once and for all