Watching the U.S. Open on television is great, but nothing beats swinging a racquet around as you actually play tennis with your kids. Don’t worry if your tykes haven’t had lessons – you can still have a blast and learn tennis basics with a wee bit of at-home research. For starters, we have some advice from NYC-based tennis pro Esther Forrester: Don’t drive your kiddos into the ground! Start with shorter sessions on the court. (Think 15 or 30 minutes.) We also recommend that you check out the videos and tips at the PlaySportsTV Web site. You’ll discover how a lighter ball works better for the younger set and can watch firsthand how kids learn the fundamentals via practice routines like getting the ball in the box five times using forehand serves. Once you’ve completed your brief (and free!) online study session, pack up your equipment and start playing at one of Chicago’s countless kid-friendly courts. Indian Boundary Park at 2500 W. Lunt Avenue is a winner and even features a mini-zoo and a pond if your brood tires of pretending it’s in Flushing, New York.