I hope my perspective of fairness isn't too far off from the mainstream because this approach has greatly reduced the exclamations of "It's not fair!" that used to be the norm in our classroom. My philosophy is simple: fair is not always equal. This was an idea that I first encountered in a conference with Brian Mendler. The team that went liked his ideas so much that we invited him to staff retreat the following summer as our main presenter. You can also read a one-page summary of the ideas and background with some research notes here.
Let's think about this a little more. Think of all the students in your classroom and the individual academic and behavioral accommodations they require to be successful. If one student needs glasses, does that mean all students should wear them? Of course not. If one student needs to sit on a wiggle seat to get her extra energy out, does that mean all students should? I don't think so. Perhaps an especially impulsive child needs a few more reminders and a few less immediate consequences. The wonderful thing about children is that they are all unique and a one-size-fits-all approach just isn't fair, even if it is "equal".
Here's a poster that I hang in our classroom. You can download it here without the watermark. With a few classroom discussions and examples, students really begin to understand what fairness is all about. It's a beautiful thing. I also like using this picture book.