The boys start their day on GREEN (ready to listen). If they behave, and make good decisions, they move to BLUE (good choices). If they continue to do well throughout the day, they move to PURPLE (great job!). If they do something exceptional, then they move to PINK (special privilege).
From green, if they start having problems like not listening, fighting with each other, etc, then they move to YELLOW (warning!). If their behavior continues, they move to ORANGE (oh no! stop!), and finally to RED (consequence).
For us, special privilege includes things like using the iPad, extra reading time with Mom or Dad, a special treat while we're out, staying up a little later, etc. We let them choose what they want their privilege to be. Consequences include things like early bedtime, no TV/iPad, time out, etc. Instead of letting them pick their consequence, I pick. I try to have them line up with the behavior they were exhibiting, or something that works best for them (i.e., no iPad time for my oldest is torture).
To keep track of where each child is, I placed their name on a wooden clothespin. The pin moves on the chart throughout the day. I think the chart works because they can visually see where they are, even as young children, based on the faces. It works well for my oldest because he strives for perfection, and always wants to be "the best," so he wants to stay on blue, purple or pink as much as possible.
My oldest's kindergarten teacher uses a similar system at school for her students. It's a card system with green, yellow, orange, and red cards. When they do something they aren't supposed to (like not listening, talking when they are to be quiet, etc), they have to "pull a card." They all start on green and go from there to yellow, orange, then red. Parents have to sign a form if cards are pulled to acknowledge what their child did. Once my son pulled his first card, it was his last. So, I knew a similar system would work well for us at home, too. :) If they are able to stay on green for the entire month, they get to pick a prize from the box. More motivation. :)
I'm hoping the chart continues to work well for us throughout the summer. I may also be adding something like a "consequence jar," full of popsicle sticks with specific consequences on each one (color coded by child). Then they would pick a stick from the jar if they hit red on the chart. This takes the pressure off me to come up with a consequence that might set off another tantrum. They pick it, they do it.
Here is a copy of the chart. It's a 3-page PDF file. The file includes fields that you can fill in for your family name, and your child(ren)'s name(s). Just print on heavier paper, trim around the color part and tape the pieces together. You can hang it anywhere that's easy for the kids to see it! I hope it works for you, too! :)