The dictator game has become a celebrated workhorse of experimental economics and social psychology. In the standard version of the game an individual is given a sum of money and must choose how to split this money between themselves and some other individual. In a variant of the game the individual must split the money between themselves and a charitable cause. This charity version of the dictator game has now been used in well over fifty studies and has provided critical insight on the motives behind giving. It also provides a simple tool that policy makers and practitioners can use to test the effect of interventions. In this paper we explain the different ways in which charity dictator games can and have been used. We also look at the external validity of charity dictator games and discuss the research questions that can be appropriately studied using them.