sack out
     v : go to bed in order to sleep; "I usually turn in at
         midnight"; "He turns out at the crack of dawn" [syn: {go
         to bed}, {turn in}, {bed}, {crawl in}, {kip down}, {hit
         the hay}, {hit the sack}, {go to sleep}, {retire}] [ant:
         {get up}, {get up}]
Source: WordNet® 2.0