Here's a cool site from the New York Philharmonic with lots of fun stuff to do!
New York Philharmonic for Kids
Check out these fun activities from the Dallas Symphony Orchestra including musical baseball!
Dallas Symphony Orchestra for Kids
Fun games for the string player
Fun Games for Strings
A fun site to learn about music - even has an online composer!
Learn about music
Check out this cool website from the SanFrancisco Symphony Orchestra:
SanFrancisco Symphony Orchestra for Kids