All around cool guy Nathan is setting up a round robin writing exercise. And he's lassoing as many people as he can. Sorry, Nathan, I can't do it (I have too many other invites waiting for my attention, like Matt W's), but I can evangelize for it. He has some interesting twists to the standard shared story meme, like changing one major plot element. That could make for an interesting reading/writing thing. Although, most of those stories tend to end up with an "and then the dinosaurs ate them all" kind of conclusion.
At the last Confusion there were a few writers who had recently completed collaborations (hey, Tobias). Those kinds of projects have always thrown me. I have no compulsions about sharing ideas (see name of blog or "Da Rules" if you don't know), but writing together right now is way far out of my skill set. I guess as a ersatz art director from back when titles in my day thing used to actually mean something, I'm used to assigning work that I've thought I've been pretty damn precise about my instructions (here's a damn sketch, follow it), but have always been surprised at what comes back. At first it was pretty hard to accept others interpretations of both the project and my "exacting descriptions and instructions on what I want to see, damnit." But then I mellowed out, although I'm a stickler for production values (really, I'm a rat-assed bastard for them. When I say use style sheets, I mean uses the fargin' style sheets). So I was really interested in how they handled it. For some it was a "I write one line, they write the next" kind of thing. It still confuses me.