"Buffalo buffalo Buffalo buffalo buffalo buffalo Buffalo buffalo" is one of the longest, if not the longest, sentences using only one homophone.
In this case, the word "buffalo" has three meanings:
Replacing "buffalo" meaning animal with "person" and the buffalo verb with "intimidate," "Buffalo buffalo Buffalo buffalo buffalo buffalo Buffalo buffalo" can be translated as "Buffalo people [that] Buffalo people intimidate [also] intimidate other Buffalo people," or "People from Buffalo, who are intimidated by people from Buffalo, intimidate other people from Buffalo."