You should check out a college marching band. My band is two hundred and eighty something players, all on the field playing at the same time. Its amazing... I actually marched during high school. My brother wasn't allowed to, but I knew I was going the music route, and kind of insisted on it.
If you like marching bands, you should also check out the DCI competitions. They don't have any woodwinds (you can't hear us anyway... though I heard that the clarinets were loud and clear at tonights football game ^_^), but the brass players are the best of the college and high school musicians and marchers. Its really amazing. And if its one of your kids/grandkids in the competition, I'm sure they would like seeing it, as well.
(Sorry... just had to have my band nerd moment. ^_^)