The crowd at Roof is young--patrons text when they aren't admiring the view from the 27th floor. The 7,000-square-foot lounge has three bars and views of the theater district and Millennium Park. Cloud-white furniture surrounds two fire pits. Patrons can choose from 20 small plates, including baby beets with ricotta salata and almonds ($11) and grilled lamb burgerstopped with mint-cucumber dressing ($13). Private parties can reserve "the hangover," a glass-enclosed area with a table for eight that dangles, Sears Tower-ledge-style, over the street.