Pare each cantaloupe.
Cut off about 1 inch from ends of each cantaloupe.
Cut up end pieces; mix with strawberries and grapes.
Remove seeds from cantaloupe.
Cut each cantaloupe into 3 even rings.
Place rings on lettuce leaves on each of 6 plates;
cut each ring into 1 inch piece, retaining shape of ring.
Spoon mixed fruit onto each ring.
Mix sour cream, mayonnaise and brown sugar
until sugar is dissolved
and mixture is smooth. Stir in nuts.
Spoon sour cream mixture on each salad.