This paper argues that in addition to being an important source of data for a project evaluator, project humor also provides a check on the evaluator's comprehension of background and events (i.e., if an evaluator does not understand a joke, he or she has probably not attained an insider's perspective). In addition, humor becomes a source of solidarity with other project members. As evaluators project and respond to humor, they are provided with an important way of affirming their ties to the people they are studying. Humor as a source of social science data, humor in ethnographic studies (including humorous outcroppings or xerox humor in the workplace, written information and political cartoons, and folktales and anecdotes), humor as a source of validation, and humor as a source of solidarity are considered. It is concluded that humor is an important data source for ethnographic studies. The three sources of this humor include outcroppings, written sources, and anecdotes. While like most unobtrusive measures, these sources are seldom confirmatory, they do provide a useful source of validation for other information. In addition, "getting the joke" can be its own source of validation. Humor establishes solidarity with people within the culture under study, provides a source of invitation as an insider, facilitates important ties to informal leaders, and makes the work of ethnography more rewarding and enjoyable. (RLC)