This got me thinking, what if you did it in the threaded environment (like LJ's comment system for example)? You could have stories which branched and went off in all sorts of different directions.
This seems ultimately cool and must be tried, so to ensure their is one (as I've no idea what to search for to find if one already exists), I've created a community -

Feel free to join/contribute/share with others as you see fit (the rules are given on the profile page).