I've often heard people say "hyperbole" exactly as it is written, "hi-per-bole", instead of how it is actually pronounced: "hi-pear-bow-lee". How did it get such an unusually different pronunciation from such a simple spelling?
Hyperbole comes from Greek ὑπερβολή, via Latin. When English adopts words from other languages, it often keeps both the spelling and pronunciation close to those of the origin language. Since other languages have different spelling conventions from ours — in particular, in many languages, a final e isn’t silent — many borrowed words have disparities like this: compare forte, mocha, jalapeno, etc.
(Another common cause of disparities between spelling and pronunciation is that spelling is much more resistant to change, so a spelling is often a fossil of an older pronunciation: that’s where things like the silent l in walk, talk come from. But that’s not what’s going on in this case.)
It's an example of a class of words that came into English from Greek, and retained a final "-e" as a separate syllable. Most such words are either names (Penelope, Calliope, Dione, Selene) or only in technical or learned use (synecdoche). Hyperbole is one that is slightly more widely used, which is why I think it has two competing pronunciations.