* Harry Potter: He asked Cho Chang, but she turned him down. He ended up going with Hermione Granger who had been asked by Viktor Krum, but he rejected her.
* Cedric Diggory: He asked Cho Chang, and she accepted.
* Fleur Delacour: She asked Roger Davies, a member of the Durmstrang delegation.
* Viktor Krum: He asked Hermione Granger, but she turned him down. He then attended the ball with Luna Lovegood.
It's worth noting that the Yule Ball was not a formal part of the Triwizard Tournament. It was a social event organized by Hogwarts to allow the students to celebrate with their guests from Durmstrang and Beauxbatons.