I feel that the web site should have some kind of function that gives you a little piece of advice every day. A tip on pedaling, sight reading, whatever. I've always thought that kind of thing makes a site have a bit more personality, know what I mean? I think with the right spin, we could attract some kids too!
This would be my plan for implementation:

TADA!
Kids love tickling Elmo, because he makes that funny laughing noise. Now what if kids loved tickling Elmo, and he gave them advice on playing the piano? You could waggle your mouse under Elmo's armpits and he'd cheerfully give you piano tips between giggles!
Now, the idea gets even better! Switch Tickle-Me-Elmo with Bernhard! You tickle Bernhard and he gives you piano advice! And if you tickle his feet, you can send him an email asking for help, and he'll write piano advice back to you punctuated with the occasional "HEE HEE" or "HOO HOO"! But if you stop practicing, he tells you to leave the site and never come back again!
I think this would really appeal to the younger crowds. Is this idea awesome or what!?!