"I hope Luna always commentates from now on... Loser's Lurgy..."
-Ron to Harry, later in the Hospital Wing (HBP19)
Luna provides commentary for the fourth match of the season. McLaggen grabs a beater’s bat and cracks Harry’s skull, knocking him unconscious. Hufflepuff wins 320 points to 60 points.
Harry is taken to the Hospital Wing.
One week earlier, when Ron was poisoned, McLaggen had pressed Harry about allowing him to fill in for keeper.
On Ron's birthday (1 March), McLaggen states that the match is in one week. This would put the match on 8 March.
The essay "An Almanac of Quidditch at Hogwarts" points out that this "appears to be the first Gryffindor game in seven seasons involving only one Weasley, unless Bill played on the Gryffindor team alongside Charlie."