For the ultimate pain-free educational experience, head to the Museum of Science. The demonstrations, experiments, and interactive displays introduce facts and concepts so effortlessly that everyone winds up learning something. Take a couple of hours or a whole day to explore the permanent and temporary exhibits, most of them hands-on and all of them great fun.

Among the 500-plus exhibits, you might meet an iguana or a dinosaur, find out how much you'd weigh on the moon, or climb into a space module. Activity centers and exhibits focus on fields of interest -- natural history (with live animals), computers, the human body -- as well as interdisciplinary approaches. Investigate! teaches visitors to think like scientists, formulating questions, finding evidence, and drawing conclusions through activities such as strapping on a skin sensor to measure reactions to stimuli or sifting through an archaeological dig. In the Seeing Is Deceiving section, auditory and visual illusions challenge your belief in what is "real." The Science in the Park exhibit introduces the concepts of Newtonian physics -- through familiar recreational tools such as playground equipment and skateboards. Visitors between October 11, 2003, and March 7, 2004 can see an exhibit called "Magic: The Science of Illusion," which looks at entertainment magic through four illusions, including levitation.

The separate-admission theaters are worth planning for. Even if you're skipping the exhibits, try to see a show. If you're making a day of it, buy all your tickets at once -- shows sometimes sell out. Tickets are for sale in person and, subject to a service charge, over the phone and on the Web (www.tickets.mos.org).

The Mugar Omni Theater, which shows IMAX movies, is an intense experience. It bombards you with images on a five-story domed screen and sound from a new digital system. The engulfing sensations and steep pitch of the seating area will have you hanging on for dear life, whether the film is about Mount Everest, bears, or wild chimpanzees. Features change every 4 to 6 months. The Charles Hayden Planetarium takes visitors into space with daily star shows and shows on special topics that change several times a year. On weekends, rock-music laser shows take over. At the entrance is a hands-on astronomy exhibit called Welcome to the Universe.

The museum has a terrific gift shop, where toys and games promote learning without lecturing. The ground-floor Galaxy Cafés have spectacular views of the skyline and river. There's a parking garage on the premises, but it's on a busy street, and entering and exiting can be harrowing.