I'm not willing to accept that it's impossible to create a legitimately enjoyable game experience in the confines of the short attention span Facebook model, though. Scrabble, for example, lends itself perfectly to asynchronous, light, casual play (cf Scrabulous, Words with Friends). But it's legitimately fun at the same time. You're rewarded for imaginative approaches to solving problems. You can play with no skill or lots, but either way, you'll always find ways to get better. Most important: You're genuinely spending time with your friends. Sharing an experience that creates a memory. This is a big deal. This is missing from almost every other pseudo-social game.