I push my students to go out and experience art they way it is meant to be seen, in a museum. From books, powerpoint presentations, and the web, no one can feel the true impact of a work of art unless it is seen in real life. Colors are changed, true size is distorted, areas are cropped, all for the sake of presentation through different mediums.
I feel it is essential to have students go to a museum at least once a semester. Make it part of their assignment and their grade. Research free museum days. If your students are struggling financially, contact the museum, they are often willing to make accommodations and often give free tickets to schools. Live too far from a museum, speak to the school and arrange a field trip.
Not everything can be learned from books and the internet, certain things should be experienced and felt first hand.