Ever thought that it would be cool to just collaborate with others while writing a document? Well ok, there are wikis but I mean real-time. Not that it’s new or anything (google docs, wave), but EtherPad recently became one of my favorites for this (thanks to Andreas Wagner).
It’s a no login website, you just need the URL and can start. You can host EtherPad yourself if you don’t trust the server.
It’s a great tool for brainstorming in a group (no more poor guy having to log everything, simply add it yourself), writing down some thoughts, coordinating things in a very interactive way.