The Aquabats. They were superheroes with silly outfits, silly names, and silly songs. They put on some of the best live shows you have ever seen and Mommy and Daddy used to go to their shows and fling their arms and legs about in reckless abandon as The Aquabats sang upbeat songs about lobsters, aliens, giant monsters and such." It's going to be a long conversation and the Q&A session at the end might be fairly involved. I will say this: if you simply do not get how awesome The Aquabats are in all their geeky charm, there is nothing I can do for you. Either you get it or you don't. Either you're invited to the pool party or you're not.
Addendum: I probably won't have to have the little chat with my daughter about ska after all. I've gotten her started on Yo Gabba Gabba (aka the greatest kids show ever) and she's seen and gleefully bounced up and down to the Aquabats. Thanks DJ Lance.