The book gives several ideas for the "random-picking" aspect of the technique, and one is a "yes/no" box. I think this would be particularly effective for younger students (PreK-2nd). You can use a shoebox, bowl or anything else. When the class (not just individual students) performs a behavior you want, write "yes" on a slip or paper or notecard. When they do something you don't want, write "no". Put the slips in the box and keep them there until it's time for the drawing. I would also consider using smiley faces and sad faces in lieu of "yes/no" for the very young ones, since they will probably find them familiar.
At intervals, pick a a slip from the box without looking. If you pick "yes," they get a mystery reward. If "no" then they don't. They should come to realize that the more they are given "yes" slips, the more chances they have for a reward. Conversely, each "no" slip helps ruin their chances.
I like classroom/team motivators because they help students work together towards a goal. What I like about the book is that it recommends being SPECIFIC with students about what types of behaviors we want to see. A "good job" is ambiguous. We want students to know exactly what they're doing right so they can connect that behavior to the reward; likewise, they need to know exactly what they're doing wrong. The book suggests using the rules and expectations you actually have posted in your classroom as a guide. That way, there won't be any confusion about what they're supposed to be doing. For instance, if the class gets a "no" slip for talking while you are, make sure that rule is specifically posted somewhere for students to see, and that you've gone over it with them. Pinpointing a few, specific behaviors for the "yes/no" box will help fine-tune the classroom's focus. If getting out of their seats is your class' biggest issue, make that the one thing that earns "yes/no" slips. If they have a real problem turning in homework, focus on that.
I would suggest being liberal with the "yes" slips when first implementing the technique, and doing drawings on a daily basis. That way, kids will have a chance to see how it works and experience the reward once or twice. Then, I'd adjust the amount of slips and decrease the drawings to once a week.