Historical clue formulations

• "It's a Mad, Mad, Mad, Mad World" co-star — 2021-03-25
• Star of "Your Show of Shows" of 1950s TV — 2020-02-23
• Early TV comic known for "Your Show of Shows" — 2018-02-05
• 1950s TV personality who appeared in "Grease" — 2017-09-16
• *"It's a Mad, Mad, Mad, Mad World" actor, 1963 — 2017-03-14