People want to be happy: a happy life is a desirable life. Can you design for that? In other words, can you design products that make a positive contribution to the happiness of people? This was the challenge of 22 design students of the Faculty of Industrial Design Engineering of the TU Delft. In cooperation with the Kaap Bélvedère society, they designed ‘rooms of happiness’ for 11 Rotterdammers – rooms that make these Rotterdammers happy. The students discovered that a happy life is a meaningful life. Their designs are therefore based on the sources of meaning of the Rotterdammers: their talents and skills, the way in which they contribute to others. The result: 11 happiness designs.