While I'm at it I wanted to address international collaboration:
First: Many conferences, seminars, etc. are much more willing to take on projects that address not only collaboration through different disciplines but also international collaboration. I have had some first hand experience with this: I co-chaired a session at a conference in Ghent with a colleague of mine at the Polytecnico di Milano. However, to be honest, it was more of an excuse to spend time with my friend than it was a true collaboration. I am not dissing this type of collaboration, as I think it fits into the "let's have fun" category--but it would be truly amazing if international collaboration could happen along the lines of intellectual interest and not just friendship.
This is a short post, I know--but I am always willing to hear feedback or especially to hear ideas for international collaboration. Because, while it is much easier to get a paper, session, etc. accepted because you are collaborating across countries, it would be even more valuable for this to have repurcussions not only for friendship but for ongoing collaboration and learning experiences.