Spoiler warning! I haven't seen 2001 A Space Odyssey and am sad to have learned that… can you edit to warn people?
Captain tomhow: "But everybody's having such a good time."
Major dang: "Yes, much too good a time. The discussion is to be closed."
Captain tomhow: "But I have no excuse to close it."
Major dang: "Find one."
Captain tomhow: "Everybody is to leave immediately! This Hacker News discussion is closed until further notice! Clear the thread at once!"
DonHopkins: "How can you shut us down? On what grounds?"
Captain tomhow: "I am shocked -- shocked -- to find that films are being spoiled in here!"
infotainment: "The ending you requested, sir."
Captain tomhow: "Oh. Thank you very much. Everybody out at once!"
Or perhaps box in your case, speaking of spoilers.