Alfred shares an anecdote about keeping secret recipies within the family.  I have a similar experience.  There's a dish called tamales that we make a couple of times a year.  It's different from the Mexican tamale in that the Mexican tamale is corn-based.  The Filipino tamales uses rice flour and coconut milk.  It's topped with chicken, eggs, chorizo and a few other things.

Several people have asked for our recipe and we've said no each time.  When it comes to secret recipes, I'm not a believer in open source.