In today’s push for shorter and quicker hospitalizations, everyday life often becomes a place of rehabilitation for people after they undergo surgical procedures. In order for hospitals to manage shortened periods of admission and to facilitate post-operative rehabilitation, a patient‘s active engagement has become a central element to clinical treatment and care in Denmark. For example, in the recovery from orthopedic surgery, sleep becomes a type of "homework" assignment that is a vital element of the patient‘s rehabilitation trajectory. Building on the theoretical concept of ‘engagement’ developed by Gilles Deleuze and Félix Guattari (2005), we examine the patient‘s relation to sleep as part of recovery; we refer to this as 'sleep engagement.' In particular, we analyze sleep as part of an institutional pedagogy in rehabilitation, and we ask how this pedagogy mobilizes rehabilitation for older patients after they have been admitted to the hospital for an orthopedic surgical procedure. Using ethnographic material, our analysis leads to a discussion of institutional expectations for what it means to be engaged in one's own patient trajectory. The article presents three results: 1) Expectations of sleep as an institutionally defined homework assignment are fulfilled through the establishment of the ‘rehabilitable and non-rehabilitable body’; 2) As an active attempt to mobilize resources in rehabilitation, patient sleep engagement becomes part of a historical and contextual nexus; and 3) Institutional sleep potential creates new points of ambivalence—on the one hand, sleep is an optimization-promoting requirement in order to exercise while, on the other hand, the midday nap reflects an outdated view of old age that opposes an active lifestyle perspective.