Historical clue formulations

• *Especially memorable, as a day — 2016-05-17
• Kind of day — 2016-04-02
• Having special significance — 2014-12-07
• Memorable — 2009-05-29
• Memorable — 2006-04-07
• Important, in a way — 2004-07-11
• Outstanding, as a day — 1996-09-23
• Like some days — 1996-05-03