Good, relatively simple summer dessert for crab feast?

Cook’s Illustrated’s lemon bar recipe is very good.

Fruit salad - great this time of year with cantaloupe, stone fruit, grapes, cherries, mangoes, berries of all types.
depending on the fruits used, add a small amount of sugar to bring out the juices.

To gussy it up a bit, top with toasted pecans (can keep them in a separate bowl to sprinkle on top so they don’t get soggy). Refreshing and delicious! people consume mass quantities of this, in my experience.