This is a very easy drill to set up and run and because of the competative nature you will find that the kids usually give a 100% effort so it makes it great for conditioning.

Set up an area 20 yards wide and 30 yards long (the zone). One player is the shark and their job is to pull everyone's flag before they can make it from one end of the zone to the other. The other players (minnows) all line up at one and on the coaches command try to make it from one end of the zone to the other without getting their flag pulled. Once their flag is pulled they are out until the next round.

Variation: Add multiple sharks.