I wrote a tool in Excel that allowed me to build word lists for different "categories" (i.e. "action words", "animals", "places", "people", etc.) Then on another sheet I could type in funny fortunes using this format:
You will slip on a [food] and fall into a giant vat of [food_plural]. A large [adjective] [animal] will lick you clean.
(This might create a fortune that looked like this: "You will slip on a kumquat and fall into a giant vat of chocolate pudding. A large hairy lizard will lick you clean."
Everything was going great until a few days before launch. I was on the bus to work, adding some last minute fortunes, when I came up with this one:
You will travel to [place] and [action word] many [adjective] [animals].
Seems pretty safe, right? Figured it would generate fortunes like this: "You will travel to Timbuktu and tickle many slippery zebras." Imagine my horror when I hit the "Generate Fortune" button and my lovely computer randomly generated THIS fortune:
"You will travel to Africa and capture many colorful humans!"
I literally gasped, and very nearly fell off my chair on the bus. Needless to say, I had to pour over all the word lists and look for other potential issues. (I found the word "hairy" in the adjective list and "clams" in the plural animals category... we had a lot of grandmothers playing so that was clearly a heart attack waiting to happen.)
I'm sure I didn't find everything, but I never heard about any complaints so I guess it worked out okay.