Basic story is now pretty well known: King Richard goes off to fight a war, his brother (Prince John) stages a coup, screws over the Saxons with some crazy taxes and some heavy-handed repressive action (he is a Norman by the way). Robin and his boy Will don't particularly like being told where they can and cannot hunt or that the reign of Prince John is a bit on the evil side. So, Robin and Will go about putting together a crew of rag-tag, repressed individuals (think Blues Brothers "we're putting the band back together" but with bows and arrows). Prince John, Sir Guy and the Sheriff do their best to keep up with Robin, they even capture him at a well planned trap (taking advantage of Robin's rather large ego). But, regardless, Robin and company just can't be outwitted and boy do the people like the little charming so and so. Oh, in the end Richard returns, Robin gets the girl and the regime becomes the integrated, respectful autocracy it was.
Film: American in origin (1938). Film information.
Interesting use of the Robin Hood name/myth/popularity: The Robin Hood Foundation