Every kid in Pittsburgh should have a chance to go to the Children's zoo. It's a nice facility that is clean, relatively safe, and filled with knowledgeable staff that care about the animals. They have many exhibits that you could spend hours looking at. (It depends on how long your kids like to watch each animal.) Once you take your child there once, they are likely to want to go back again! Parking in convenient and I have found that it is usually less crowded on week days than it is on weekends.