Facebook is a haven for simple social games these days -- emphasis on simple. The gameplay frequently consists of nothing more than a few clicks and then waiting for the game to do what it wants to, a type of mechanic once memorably referred to as sandwich gameplay. (There's nothing interesting for the player to do, so you may as well get up and make yourself a sandwich.) And yet games of this breed can acquire more subscribers than World of Warcraft, which is one of those concepts that seems baffling at first, but once you think about it, it's still baffling.
The games are certainly massive, multiplayer, and online. About the only thing we could argue they're not is games, since there's little to no skill involved at the best of times. But they certainly don't seem to have problem bringing in money or subscribers, and they're becoming omnipresent. Do you take part? Do you play one or two because your friends do, or several of them? Do you use them to eat up downtime in your game of choice, or do you play them on their own merits? Or do you dislike them precisely because they're barely-disguised treadmills?