Group activity with authentic material

Here, I'd like to implement an example of an activity working with authentic material; in this case a song with its lyrics video.

The student's level would be 9th grade (Junior high)

Students have to identify the irregular verbs (present or past) within the lyrics of the song and try to write them all per teams. After the song ends, they will tell aloud the number of verbs they found and the winner will be the team with the closest number, or the exact number of irreglular verbs.