In the book Jack climbs up a magic cornstalk and meets helpful giants who teach him about corn, and in the end there is a corn maze (which Jack uses as a way to communicate with the giants, which is actually a pretty clever idea).
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There are other corny twists (yup, pun intended) on "Jack and the Beanstalk" out there, such as a modern adaptation starring a girl, Waynetta and the Cornstalk, which is recommended as a good educational story to compare and contrast to the traditional fairy tale.
There are some other folk tales out there related to Jack's magic beanstalk, but in America they've naturally been altered to feature corn, a very prominent plant here in the Midwest. Here's a brief tall tale from Kansas featuring a boy who climbs a corn stalk to look out at the corn field and got stuck on a growing plant. Not quite as fleshed out as "Jack and the Beanstalk" but I'm sure it was influenced by the story and adapted to a corn growing culture.