One of the most surprising things about the Corpus Callosum is that lesions to it, as well as its complete destruction, cause almost no changes to higher cognitive function, at least easily noticeable ones.
Once upon a time, doctors had a joke about the Corpus Callosum, that its only function was to carry seizure activity from one hemisphere to another. They actually tried to test this joke out, by cutting the corpus collosum in people with life-threatening epilepsy. And since they didn't believe it would cause any problems, they didn't find any.
It was only some years afterwords, that they noticed that subtle loss in mental function followed cutting the corpus callosum. These effects mostly involve such things as language ability, and the ability to use one hand or another. Some of these are a bit bizarre. For example, a person with could pick up a plastic duck with their left hand, and know what it was, but not be able to say plastic duck, because the right hemisphere controls the left hand, while language is mainly stored in the left hemisphere, which can't communicate with the right hemisphere without the corpus callosum.
I also personally think that many creative activities would be impossible without the corpus callosum. For example, freestyling, the act of putting together rhymes on the fly would be impossible without the language and music centers working together.
Bay area rapper Del has an album called Both Sides of the Brain, but unfortunately, I don't know whether he managed to rhyme corpus callosum with Oakland. He should have, though.
Also misspelled corpus collosum.