fish fish fish fish fish

It's a well known linguists' paradigm -- the seemingly nonsensical string of words that can actually be parsed as a grammatical sentence.
Fish fish fish fish fish.
In other words, flounders that groupers eat hunt flounders.
Still don't get it? Think about the phrase "games people play" -- it's elliptical (the expected "that" is omitted) for "games that people play." Same thing for "fish fish fish" -- it's an elliptical noun phrase serving as the subject of the longer sentence. But be careful -- it works best when the first "fish" is the object of the third "fish" within the inner phrase structure...

There are many fun examples of this phenomenon -- write in with more!
(for some reason, most of them involve animals...)

• Fish fish fish fish fish fish fish.
• Buffalo buffalo buffalo buffalo buffalo buffalo. ("Buffalo" can be a place, an animal, and a verb. Look it up! If you still can't parse it, let us know.)
• Geese geese goose goose geese.
• Sheep fish goose fish sheep. (Whether it's actually possible to "fish sheep" is an open question in my book.)
• Fish Fishkill fish fish kill fish. (Fishkill, NY acts as an adjectival modifier.)
• Buffalo geese Fishkill dogfish fish kill Buffalo sheep.
• Help help help help help. (Thank you, Dracubeth, for that worthy submission!)
  

the possibilities are nigh endless....in whimsy and ludicry!