She is Beauxbaton's (that hard-to-pronounce French school's) champion (I won't bother checking the book in order to spell it right - it's Rowling's fault for making it so * * * * hard to pronounce), half Veela, and with a temper and attitude to match.
She never does that ugly-hag-spit-fire-in-your-face thing, but with a half-Veela you never know, do you? *Shudder*
And... well, er... let's see. She appears at Hogwarts, participates in the tournament (you know which one), subsequently comes last, and leaves a much nicer person. Some people...
Anyway, Harry saves (ha ha) her sister from drowning (ha ha again... sucker - you guess which one), and thus she is nice to him ever after. As I said, some people are odd.
She leaves Hogwarts at the end of Book 4 with the hint of a return (please Rowling, not as the DADA teacher - PLEASE!) and a slightly more important role later in the series. Who knows... she might even... she might even... I dunno. She might do something, at least.