ABOUT 30 senior citizens and 50 children gathered for a day of fun and laughter last Saturday when they performed in the Children and the Elderly Summer Variety Show at Central's Caritas Hall. The concert, the final event of the Joint School Summer Project, featured a Chinese opera, games, clowns and a fashion show with links to a Judge Pao story. This year's winner of TVB's New Talent Singing Contest , Hoi Chun-kit, and last year's winners, Cheung Shun-tak and Cheung Shun-kai, sang their new songs. The project, which started in July, was organised by Maryknoll Convent School, Marymount Secondary School, St Joseph's College and Raimondi College. It provided voluntary services for residents of an elderly people's home and for children from three temporary housing areas. Various activities, including outings to country parks, a visit to a soft drink factory, a games day and interest classes, were held over two months. ''Through the project, I have learned more about the quality of life of children in temporary housing areas and come to understand the temperament and characteristics of the elderly,'' chief organiser Gloria Lau Sau-sau said. ''All the children we worked with are very active, so you have to really play with them to understand them,'' the Marymount Secondary School student added. ''When working with old people, however, you have to be patient and listen to them.'' Gloria said the organisers had brought young and old people together deliberately. ''These two groups of people seldom have any chance to get to know each other's lifestyle,'' she said. ''But by planning a range of performances and mixing the interests of both, they are given the opportunity to appreciate each other's way of life.''