If you share a house – and maybe even if you don't – you'll benefit from having a master calendar in the kitchen.
Get or make one with big squares to write events.
Things that should go on here include:
– dinner guests/parties
– house guests
– medical appointments
– household members out of town
– holidays when household members will be around home instead of off at work/school
– deliveries or repair appointments
– "Mail rent today"
– parent/teacher conferences
– any special event where one household member will be getting a ride from another ("Suzi's soccer game")
– household and significant other birthdays
The ideal spot for this is on or beside the fridge, especially if that's also near the kitchen phone.
Near it can be the shopping list, any shared bills that need to be reviewed (e.g. the phone bill), and the current list of who's doing which chores (or as we used to call it in my household "The Wheel of Torture").