For me:
Great Outdoors
Weekend at Bernie's
Breakin
Karate Kid
Stand By Me
National Lampoon's Vacation
Summer School
Heavy Weights
Meatballs 3 (Loved it since I saw it on USA up all night)
Sandlot
Summer Rental
Caddyshack
Yeah Meatballs!
I think i might throw in Teen Wolf in this too. Bill & Ted's Excellent Adventure
Iron Eagle
Beast Master
Toy Soldiers
Krull
Over the Top
Flight Navigator
Short Ciruit
The Last Dragon
Revenge of the Nerds
I watch all of these multiple times during summer break