Captain Crunch is most famous for a whistle they included in the box as a promotion back in the sixties. Its perfect pitch did a number on the world's long distance telephone system (this was before the telcos figured out that in-band signaling was not a good idea).
The cereal was formulated by Arthur D. Little, a Boston consulting company. Aunt Pam's cereal
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Wow - never heard the whistle angle before - I thought it was bad enough they made a cereal that made me bleed from the mouth...