Friendsvite is a way to know "who brings what" at an event without the hassle of login in or anything like that. Just create an event and share the code or the link on your facebook event/doodle, and people will be able to pick what they need to bring. The project is still in beta but fully usable, I'd love to hear any feedback about how useful this thing could be to you. I tried to make it as simple as possible, without accounts or anything :)