Luna Lovegood
Soon after the Party, Luna was the commentator at a Quidditch (which is a game played at Hogwarts) match, in which she went off on side topics by saying that the Hufflepuff Chaser, Zacharias Smith suffered from Losers' Lurgy and she also pointed out oddly shaped clouds, and often forgot players names. Although Professor McGonagall was annoyed, a lot of students found her commentary highly amusing. At the end of the year, Luna patrolled the corridors in search of Death Eaters.