Which sonnet was in the movie Ten Things I Hate About You?

The Sonnet that Julia Stiles recites at the end of Ten Things I Hate About You is an original composition by Karen Lutz and Kirsten Smith (who wrote the screenplay). It has a lot of very obvious debts to 'real' sonnets by Shakespeare, but at the same time it also stays in character with the screenplay.

There are lots of films, stories, songs &c. which are 'based on' ideas by Shakespeare. I think Bill would have shrivelled up with embarassment if he ever heard Taylor Swift. But I'm nearly sure he'd have chuckled along comfortably with Ten Things I Hate About You.