Startup Idea: Instantaneous online group chat

I often need to talk to colleagues in group fashion. I also do not want to go through the hassle of registering for a service to do this.

Is there an online service that would simply generate a hash key url to a chat room that I can then use to invite people and start a chat? The key here is its simplicity, it should be less than 10 seconds to set up a chatroom, just like posting on posterous.