Historical clue formulations

• Funny joke, in slang — 2023-03-14
• Hilarious joke, in slang — 2019-06-09
• Thigh-slapper — 2016-02-24
• Funny, funny joke — 2015-11-11
• Real hoot — 2014-12-23
• Knee-slapper — 2005-05-08
• Knee-slapper — 2002-02-17
• Knee-slapper — 2001-07-08
• Quite a joke — 2001-03-07
• Thigh-slapper — 1999-09-19
• One very funny joke — 1999-02-23
• Joke that causes a belly laugh — 1998-04-07
• Super joke — 1994-10-31