Unroll the crescent rolls and place in an ungreased 15-in. x 10-in. x 1-in. baking pan. Flatten dough to fit the pan, sealing seams and perforations. Bake at 375 degrees F for 10 minutes or until golden brown. Cool.
In a small mixing bowl, beat the mayonnaise, cream cheese and ranch dressing mix until smooth. Taste the mix and if desired mix in garlic powder. Spread over crust. Top with the vegetables of your choice. Sprinkle with olives and cheeses; press lightly. Cover and chill for at least 1 hour. Cut into squares.