If you are going to incorporate an exhibit or performance into your course, put it in your syllabus and begin mentioning it from the first day of the semester.
Exhibits, special collections visits, etc.
If your course meets on the same campus as the exhibit, it’s best to meet the students in the classroom and walk them over to the library, museum, etc. Otherwise, give explicit directions in your syllabus.
Ask the students to do something (besides look around) while they are at the exhibit. Some instructors ask students to choose a particular object or image to write about, note down its title, date, etc., and write a brief explanation of why they have chosen it. You could also ask students to find several examples of a particular phenomenon you’ve been discussing in class, or do a short compare-contrast between two items.
Plays, concerts, lectures, conferences, readings, etc.
Students need a good deal of warning if your course will require them to spend time outside class and money on something other than books. It is fine to require attendance at such an event, as long as you announce in your syllabus the expense and the dates. Some students may not be able to attend a single poetry reading because of their family and work commitments. But a play performed once or twice a day for two weeks, or a conference held over two or three days, should be possible for every student, especially if the dates are made clear in the syllabus from the beginning of the course.
It’s a good idea to ask students to write informally about their impressions and to debrief in class on the first day after everyone has attended the event.