I am mildly addicted to the game Farm Story for iDevices. I presume it is ideologically related to the facebook farming game, but I never could get into facebook games enough to know how similar they are or are not.
They offer up the game for free, and don’t have any ads in game. You can play fast growing plants or slow growing ones, so if you only want to touch it once a day, you can play it that way. Where they make their money is on ‘crystal’ sales. There are certain items you can only buy with crystals, and expanding the size of your farm is much easier with them. Without them, you need lots and lots of ‘neighbors’. This morning, it occurred to me that really, everyone wants more neighbors, and so anyone posting to someone’s wall asking for a neighbor will accept a friend invite from pretty much anyone. So now, whenever I stop at a farm to water, I check the wall, and if there are any people leaving their ID, I’m sending an invite. The response has been very fruitful.