What are the names of all games that were played for at least 1000 hours?
SELECT gname FROM Plays_games AS T1 JOIN Video_games AS T2 ON T1.gameid  =  T2.gameid GROUP BY T1.gameid HAVING sum ( hours_played )   > =   1000
games that were played for at least 1000 hours refers to SUM(hours_played) >= 1000;