For adults, give them the task of learning about a Prophet for example, and have them talk about it at one of your family revision times. This motivates everyone to want to participate and ultimately, it improves their knowledge of the Quran and their intellect.
Learning the Quran as a family is one of the best bonding activities that a family can engage in. It is an act that not only improves your relationship in this life, but also bonds you towards an everlasting reward in the hereafter.