We refer to them as "scrums"... diving on loose balls. Securing a few loose balls (for a few extra possessions) can make all the difference in a close game ... plus it sets a tone of "scrappiness" and toughness. A great hustle play is often a great team motivator and energizer. Here are a few loose ball drills.
This is a good drill for emphasizing hustle and going for loose balls. It also works one-on-one offensive skills, man-to-man defensive skills, and rebounding. A "laid back" player can actually be taught to hustle and get after the ball and the opponent.