Spread 1 can refried beans in bottom of a 10 inch pie plate. Mash 2 peeled and pitted avocados with a tablespoon of lemon juice and spread over refried beans. Mix 1 (16 ounce) container of sour cream with 1 package taco seasoning mix and spread over avocado layer. Chop 2 tomatoes and sprinkle over sour cream mixture. Chop 2 onions and sprinkle over tomatoes. Chop 1 can olives (pitted and black) and spread over onions. Grate 1 (10 ounce) bar of Cheddar cheese and spread over top. Serve with tortilla chips for scooping up layers.