My own secret hope is that one day soon there will be a genuine Harvest Moon game created for Facebook. Meanwhile, with the advent of the English Countryside in Farmville, one can play a game that reminds one quite a lot of Harvest Moon.
The English Countryside is a location where players who have reached Level 20 or higher in Farmville can own a second farm. In classical Harvest Moon form, you will be asked to rescue a dilapidated estate by an elderly gentleman who arrives on your land in an old-fashioned airship and who, after you help him with the repairs, will invite you to journey back home with him.
The English Countryside offers a sequence of Quests to allow players to obtain necessary buildings and animals, introducing them to new Crops and the ability to raise hybrid Animals that did not exist in the original Farmville.
Quests have become more frequent in Farmville over the past year, appearing generally to mark holiday seasons such as Christmas and Valentine's Day. They usually require the planting and harvesting of specific Crops, interactions with Neighbours/Friends to obtain specific unique items with progressively more valuable Rewards for each task in the sequence.