Best drill -- competition

As long as we're doing the same Escape from Baghdad, we also did it.  you can make the area as big as you want.  For the sake of explanation I'll say you have a total perimeter that is 10 yds by 5 yds.  Cut it in half so that you have box A which is 5 yds by 5 yds and box B which is 5X5.  You have teams of 3.  2 offensive blockers and a ball carrier and then three defensive players.  Only one defensive player is involved in the drill at a time.  Your offensive blockers are designated to just one area, so one is blocking in Box A and one is blocking only in Box B.  The ball carrier can run back and forth between the two boxes.  The defensive player starts outside the perimeter.  You tell him he has 10 seconds, for instance, to get a wrap on the ball carrier (we quick whistle on ball carrier for fear of twisting knees etc, with all the mayhem this drill creates).  on the first whistle the defensive player gets in the perimeter and goes for the ball carrier.  in box A he can only be blocked by one blocker and in box b by the other blocker.  He does whatever he needs to do to get off blocks etc and get to the ball carrier.  Rules can include no low blocks, if defender is down you allow him to get to his feet, etc.  Basically if defender gets to the ball carrier, that's 1 point for the defense, if he doesn't it's a point for the offense.  

We find it gets guys acting more aggressive.  It's good for guys who try to "over-technicalize" some of their technique to the point that it cuts down on their aggression.  I hope I helped.  I could try to draw something up if I didn't help with this explanation.