In the 1970s a new form of outdoor trip programming appeared. Known as "common adventure," its best known trait is the absence of a designated leader. In 1970, Gary Grimm, the University of Oregon's first outdoor program coordinator, laid out the key principles: self-directed learning, formation of groups of people with similar interests to achieve objectives, and establishment of an environment in which participants have the opportunity to make independent decisions. Two misconceptions about common adventure programs are that program personnel cannot be paid and cannot share their knowledge with others while on trips. In actuality, common adventure advocates such as Grimm proposed a participatory form of leadership and expected leaders to emerge during trips. A lawsuit resulting from a common adventure trip in the early 1980s cast considerable doubt on the legal defense of volunteer directors and verified the contention that providing some supervision and guidance would minimize an institution's liability. Attempts to distinguish among different outdoor programming styles based on whether activities were participant-oriented or originated by an organization led to additional terms such as "cooperative adventure,""structure/safety training," and "packaged trips," which have been intermixed over the years. This paper proposes new terms such as "structured programming" and "unassisted common adventure," and mentions several unassisted common adventure programs offered in institutional settings. (Contains 15 references.) (TD)