  So one evening, during my college years, a friend and I were out drinking and went back to his apartment to hang out after last call. By the time we got there, we were really hungry--so we raided his kitchen. The only thing he had to eat was a box of Nerds cereal. If you are unfamiliar with the entire Nerds concept--it originally started as a candy. The box was divided into halves, with one half containing candy that was pink, the other half containing candy that was purple.
I believe, as time went on, Nerds came in different colors/flavors--but that isn't important here. The cereal was similarly themed--the box contained two bags of cereal. Since there was just the two of us, we each picked a color (I selected pink, my friend went for purple), grabbed some bowls and milk, and chowed down. The rest of the evening went, pretty much, as you'd expect and nothing seemed out of the ordinary--until my friend called me the next morning.
"Hello," I answered. "Hey it's me...have you taken a shit yet? " he queried. "Ah...no...I haven't," I replied. "Well, take a shit and then call me back," he said, hanging up the phone. Now, despite the odd circumstances of the request, I did my best to comply. It wasn't until several minutes after I was properly enthroned that I realized my body had no need to defecate. I waited around for about an hour, had a few snacks, then felt things moving along as I had hoped.
As I was doing my business I wondered, albeit for the first time, what might come out of me that would prompt an immediate phone call. Turning around and looking in the bowl brought out a feeling of dreadful anticipation usually reserved for investigating strange noises in the night. To my shock and horror--I noticed that my feces bore a distinct pinkish hue. The following phone call to my friend confirmed that he had a similar movement, only his bore a purple hue.
Figuring that the worst of the experience was behind us (literally), we didn't think there was much to do about the matter. A few days later I did send a letter to Ralston-Purina (the cereal's manufacturer) complaining about the amount of dye that had to be present in that cereal in order to produce such a reaction. I did get a letter back from them a few weeks later--complete with coupons for a few free boxes of Nerds cereal. 
