Beach Opening Day
On the 30th of Spring, Zack will come by and ask if you would like to join the celebration for the opening of the beach going season tomorrow. He says there'll be a contest for your dog and if you want to join he'll take your dog from you. The next day go to Mineral Beach where a crowd has gathered to watch the Frisbee Contest.
Talk to Zack from behind the counter to participate in the Frisbee Contest. Basically it's the same as when you bring your dog down to the beach to play Frisbee, except this time you only have 2 chances to get a good score. Keep an eye on your gauge and throw the Frisbee (press A) when it's close to the green top edge. Your dog will go out and chase the Frisbee. If he catches it then the length of the run is counted as a score. If your dog runs far enough then you'll be named the champion and Zack will give you a Power Berry.
The distance required to win the contest will be displayed on the sign next to the bench, behind where Zack is standing. Each person who plays Harvest Moon will have a different distance requirement to win depending on how far the dog can run.
On your first year on the farm you can't join in the festivities. Your dog isn't an adult until the 1st of Fall. Only then can you purchase the Frisbee from Won and practice until the next 1st of Summer.
Being crowned champion will earn you 25 Animal points.