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Institute is a program of religious instruction for young adult members of the church. Institutes of religion provide weekday religious instruction for single and married postsecondary students. Young single adults of the appropriate age (generally 18-30) are also welcome to attend. Although institute buildings are usually right across the street from college campuses, in some areas classes are taught in campus classrooms, ward buildings, homes, office buildings—basically anywhere people are willing to meet. Institutes provide religious classes, much like Sunday School, in order to add some spirituality to the lives of young adults. Most institutes have some common areas and activities, as well, for social interaction and fun.
Currently, over 150,000 young adults attend institute in over 500 locations. "In addition to religious instruction, institute provides opportunities to grow spiritually through service, social interaction, and leadership training. Institutes also assist parents and priesthood leaders in encouraging youth to serve missions and marry in the temple." 
(See also The Iron Rod.)