Have you seen Snap, the Syndicated Next Action Pattern? It was this great concept that Matt Webb put together for how to make RSS feeds more interactive by including forms with items so that users could alter and respond to whatever is being syndicated. It was meant for things like managing bug trackers, but I bet you could figure out a way that would be more community/fun based. Here’s Webb’s post on Snap and a video demonstrating a concept implementation called Dentrassi