Engineering studies are often too focused on the development of engineering skills. This results in graduates with deficits in 21<sup>st</sup> century skills, such as complex problem solving, teamwork, or communication skills. To address this issue, sophisticated concepts need to be introduced in order to attractively include 21<sup>st</sup> century skills into engineering curricula. This paper presents related concepts, which we have applied in the engineering degree programs, and discusses their benefits and drawbacks according to our experiences. We also provide recommendations about integrating 21<sup>st</sup> century skills courses into engineering curricula.