I went the google calendar route and it seemed a bit annoying for the family to use specific syntax etc.
I think a simple list below with options for recurring would be great. Perhaps to only show up a week prior to the event?
Change HVAC Filter: June 1st, 2017
Change Fridge Water Filter: July 2nd, 2017
Cousin Mike’s Wedding: August 5th, 2017
Grass fertilizer: August 24th, 2017
Car Oil Change: September 9th, 2017