Arts writer Christine Johnson-Duell, who has written about opera for us in the past, has a great article up on the PM site about Seattle Opera's Falstaff Family Day (tix for kids are $15, and the opera is planning a host of activities for families during intermissions). She takes down the arguments as to why kids shouldn't be exposed to the opera one by one, and most persuasively.
This past summer, my daughter was a Niebelung in one of the Ring operas, and I took my son to a dress rehearsal to watch her perform. He -- a teen whose iPod, if he had one, would be stuffed with the likes of Paramore and Airborne Toxic Event -- was blown away by the beauty of the experience. Those sets! That music! Rhinemaidens suspended in mid-air as if they were swimming in the Rhine!
Don't underestimate the kiddos when it comes to their ability to appreciate an art form they're not familiar with.