It's a word that often describes something that's humorous in a quirky or unexpected way, with a touch of whimsicalness or absurdity.
Here are some synonyms for droll:
* Whimsical
* Funny
* Odd
* Peculiar
* Amusing
* Facetious
* Wry
Example:
"The old man's droll stories about his childhood adventures kept everyone entertained."