Navy Pier is the center of Chicago's fun-life with everything from amusement park rides to theaters and restaurants. Every Friday and Saturday night they even have fireworks at 9pm. It's touristy but don't miss it when you're in Chicago.
The Shedd Aquarium is located in the Chicago Museum Campus. It is one of the most popular attractions in Chicago and has over 25,000 fish with aquarium tanks ranging in size up to 5 MILLION gallons. The Museum Campus is a 57 acre lakefront park that also is home to the Adler Planetarium and the Field Museum of Natural History. The Field Museum is also home to Sue, the most complete and best-preserved Tyrannosaurus Rex fossil ever discovered. Sue dominates the main floor of Stanley Field Hall.
In the summer, Chicago has great beaches, but without the ocean salt. The lakefront is great for walking, jogging and biking all year. In fact, you can rent bikes by the hour or day at several lakefront locations (Navy Pier, North Ave Beach, Foster Beach) and riverwalk.
Chicago is also a premier sports town and is home to the Bears, Bulls and White Sox. Checkout a home game and then join other sports fan(atic)s at one of Chicago's great sports bars, including unique locations like the ESPN Zone.
Chicago is also a great place for kids! The Chicago Children's Museum is another big part of Navy Pier (57,00 sq feet in fact!) and has over 500,000 visitors every year. It's a great place for hands on learning for younger kids.
And don't forget Chicago's incredible restaurants, fantastic festivals and street fairs and top line concerts and live theater. Chicago is a great place to live or visit for work or pleasure.