Computer science is becoming increasingly important in our society. Meta skills, such as problem solving and logical and algorithmic thinking, are emphasized in every field, not only in the natural sciences. Still, largely due to gaps in tuition, common misunderstandings exist about the true nature of computer science. These are especially problematic for high school students, who need to have a realistic view of what studying computer science would be like in order to make advised decisions about their future careers. The principal objective of Finnish high schools is to prepare young students for further studies and life in general; it can therefore be seen as something of a paradox that these schools are not obliged to provide their students with tuition in computer science. In this paper we describe the project "DASK" (DAtakunskap i SKolan, Computer Science in Schools), which aims at introducing computer science to Swedish-speaking high school students by providing university level computer science courses on the web. The purpose is to give a realistic view of computer science, at the same time removing any potential misunderstandings about its true nature. The "DASK"-curriculum includes web-based versions of the five basic courses taught at the university with no trade-offs in either contents or difficulty level. The main focus is on student activity, emphasizing the importance of continuous work throughout the courses. We have formulated the "ActiWe" (Active on the Web) principle, a main guideline applied when designing, developing and giving the courses. Instructors at the university are responsible for the courses in most ways (acting as the course lecturer, maintaining the material, checking assignments, giving feedback etc.), but each high school has a contact teacher who supports the students locally. "DASK" was initiated in 2002, and has been popular from the very beginning; feedback from both students and teachers has been positive. In a recently conducted survey (January 2005), many of the teachers stated that their schools would not be able to provide any computer science-related courses on their own, thus indicating a definite need for the "DASK"-courses. In addition, the high number of participants registering for the first course each year implies that there is a genuine interest for computer science among high school students. Our experience shows that the greatest challenges for both students and university instructors are time-related: in most schools, the "DASK"-courses are not given time in the schedule and are thus not part of the actual tuition; this leads to already stressful periods becoming even more burdensome for the students. Giving the "DASK"-courses has also proved to be time-consuming for the university instructors; much time and effort has to be invested in maintaining the material, but particularly in giving individual feedback for assignments to all students on a weekly basis. A future challenge is thus to improve the time management of both students and instructors. (Contains 2 figures and 1 table.)