I wanted to call out one nice thing about that game, Dino Run, that I linked to. The only thing that can actually kill you in the game is the pyroclastic cloud: if it catches up with you and covers the screen, it's Game Over. There's plenty of other stuff in the environment, like other fleeing dinos and giant tumbling boulders, but they can't kill you -- only get in your way. And they impede you through what seems to be a basic physics system. One result of this is that if a boulder happens to come up from behind, you can jump on it and try to ride it. That in a nutshell is emergent gameplay: it's gameplay that happens because the various components of the game interact in predictable ways to cause unpredictable results. It would be nice if whatever project I end up making out of this Mac game engine can offer some of that.
On an unrelated note, I got about halfway through the fourth episode of "24" last night, was overwhelmed by a terrible feeling of oh dear god, they're going to stretch this out for how many more months? and turned it off. I can't help but feel that this show would have worked out a lot better ultimately if they'd called it "16" or maybe even "12."