Historical clue formulations

• Play ___ in — 2012-12-21
• Play ___ — 2009-04-17
• Play ___ in (be involved with) — 2002-02-05
• Play ___ in (influence) — 2000-02-17
• Have _____ to play (be of use) — 1994-01-02
• Have _____ to play (be of use) — 1993-11-28