Playfulness can be observed in all areas of human activity. It is an attitude of making activities more enjoyable. Designing for playfulness involves creating objects that elicit a playful approach and provide enjoyable experiences. We have designed and evaluated a set of cards called the PLEX Cards and its two related idea generation techniques. The cards were created to communicate the 22 categories of a Playful Experiences framework to designers and other stakeholders who wish to design for playfulness. We have evaluated the practical use of the cards by applying them in several design cases. In this talk I will present an overview of the design rationale of the PLEX Cards together with a couple design cases where the PLEX Cards were used and evaluated.