Open since 1993, the Imaginarium is filled with enough cool (if somewhat nerdy) exhibits to keep kids having fun for a good hour and a half. They'll be mesmerized by optical illusions, plasma globes aglow with electrical charges and a pendulum that spins in a wildly unpredictable pattern. Kids can use a set of pulleys to lift an object weighing a quarter of a ton and pretend they're flying an airplane with the flight simulator. The Imaginarium also features lots and lots of snakes. Admission is charged. You can get a discount pass to visit the nearby Sullivan Brothers Iowa Veterans Museum and Rensselaer Russell House Museum as well.