We brought in a soft ice chest with ice and bottled water... AND... some hand held misters purchased at WalMart... little fans with a finger pump to disperse water. Don't scoff.. they actually work pretty well... AND, they provide for loads of entertainment spraying people when they least expect it.
Games were LOOOOOONNNNNGGGGG..... they stopped play often for water breaks, but not long for each break.. just lots of breaks. I'd say on average a youth game is about and hour and twenty minutes long... yesterday they stretched out to about an hour and forty-five minutes.
We're about to purchase a mister that's a fan with a pressurized system that sits on top of a 5 gallon bucket filled with iced water. Sold at HomeDepot, Lowes, etc. Couple other people have them and swear by them. Of course this requires a relaxing of the 'rules' about what you can take into games... but the authorities are pretty lax in this regard.... just threaten their lives and they'll usually pass you right thru.
Which brings up: I KNOW why schools, sports organizations, have the 'can't bring in water' rule... so they can make money selling water... BUT... here in the central valley, where summer temps are always around 187 degrees... this rule is inhumane and should be abolished. How you can ban water from people unless they pay you, especially in Calif. during summer, is beyond me.