Drum Corps International
An organization that holds competitions for drum and bugle corps.
It's very safe to assume that it is the most popular one of all.
Recently, it's popularuty has been decreasing by drummers, and rising by the bugle players.
The reason for this is probably because while the bugle music is getting more creative and challenging, the drum music is losing it's rudimental identity, thus being so easy that a freshman in highschool can play it.
Dude, did you see the DCI semifinals?