Sleep can be a troubling experience for persons plagued by nocturnal disorders known as parasomnias. While they are "asleep," such persons may be walking, screaming in terror, rearranging furniture, eating odd food concoctions, or wielding weapons. Or they may be unable to fall asleep because of the unpleasant sensations of restless legs syndrome. Although these disorders are indeed bizarre, effective treatments are available. In this article, Drs Schenck and Mahowald discuss the evaluation and treatment of parasomnias and provide illustrative patient vignettes from their extensive experience at a sleep disorders center.