To have enough fruit for 60 people you can use a large watermelon and cut it in half the length of the melon. Make melon balls from both halves of the melon and shave the shells for a pretty presentation. Add the balls from a cantaloupe, a few pounds of grapes, a cubed whole pineapple and fresh hulled strawberries. Toss the fruit to combine. You will need about a quart of yogurt to make a dressing for your fruit salad for 60 people.