Historical clue formulations

• Henrik Ibsen play — 2023-09-10
• Pack in Pac-Man — 2018-05-24
• Haunted house inhabitants — 2016-09-06
• Wraiths — 2016-04-20
• Haunting presences — 2015-08-13
• Visitors in "A Christmas Carol" — 2015-02-26
• Many Halloween costumes — 2008-11-03
• Common Halloween costumes — 2007-07-26
• 60-Across play — 2006-05-23
• Uncredited authors — 2004-12-16
• Some trick-or-treaters — 2003-04-24
• They're represented in sheets — 2002-10-19
• Halloween characters — 2002-08-20
• Haunted house inhabitants — 2000-06-26
• Some trick-or-treaters — 2000-03-15
• Uncredited authors — 1998-09-09
• Play by 21-Down — 1997-05-29
• Poltergeists — 1996-09-30
• Ibsen play — 1994-06-22