A user-adaptive interface is capable of personalizing its content and interaction with individual users, based on the information it has about them (user model or user profile). In several application domains (ranging from tutoring to e-commerce), user-adaptive systems have already proven to be more effective and/or usable than non-adaptive ones. Moreover, personalization, i.e. the capability of (semi)automatically addressing the features and preferences of each individual user, is more and more considered as a key factor to add value to various software applications and increase user satisfaction. Our lab works on adaptive interfaces using various technologies and considering multiple application domains. For example, in the medical domain, we have developed detailed user profiles to represent various kind of disabilities, and we are exploiting them to build intelligent emergency support systems, using Web-based and mobile interfaces; in the fitness domain, we are working on wearable systems that are able to provide personalized motivation and health advice based on the user's physiological state. We are also introducing adaptive features into 3D virtual environments, e.g. to deliver personalized virtual training or enrich the shopping experience in 3D e-commerce sites.