In a contention resolution problem a number of users try to access a common medium (channel). If two or more users attempt to access it at the same time, a collision occurs and they all fail. In that case each such player must try again later, until success. A contention resolution protocol provides access policies to the users aiming at high channel utilization. In this talk, we will be describing efficient protocols that at the same time are immune to selfish behavior of the users.