Has anyone ever participated in a 24hr play project either as a writer or director or actor?

If so, how was it run, how was it structures, set up? I'm curious about different styles.

Here's the website for the project: http://www.24hourplays.com/

I've been involved in a couple. Usually, everyone meets, the writers are given their brief, the writers write all night. The scripts are sent to the director, who then casts (or in some cases, the shows are pre-cast and the writer knows who they are writing for. It varies). Everyone rehearses all day. At night, they are performed. That's it.  Sometimes the nights are themed. Sometimes the writers are given a prompt of some kind: a prop, a phrase, whatever. The more skilled the participants, the better. People with a lot of improv experience are usually great. There's a reason why for the Big Time ones, people like Rachel Dratch, Parker Posey & Tina Fey have been involved.

Having done this in the 90s, universal email has made it both easier, and less fun IMO.  They've also become a kind of default fundraier show for many, many theater companies. I think it's a fun exercise, but that's about it. JMO.