Send them fresh flowers every month.
Make reservations at the new eatery.
Bring them out for a dance party.
Plan a massage for two people.
Take a picnic with them outside.
Write some personal love letters.
Schedule a date at the art gallery.
Obtain tickets to their preferred performance.
Give them a present they don't want.
Make a nighttime stargazing excursion.
organise a dinner gathering for their pals.
Go on an unplanned excursion.