70th birthday party.

Use multicolour. Arrange the photo exhibition (even that person's childhood photos) of the person who has reached 70. Many people would not have seen those photographs. Good food. Some one senior and some one most junior in the group to wish the birthday person a happy birthday. Present him a gift which he always wanted - a good walking stick, a sweater, a shawl? Have preparation of his favourite dishes, Decorate the house, Serve food.