I am a new doctoral candidate of information and computer science and about to initiate my research, and typically collaborate with my supervisor and other group members. But seldom will a researcher limit his collaborators to those within the department he's in; he has to enlarge his network. I believe energetically participating in academic activities/events surely brings benefit. As a student, my quick thoughts are, for example, applying for internships at some research institutes, summoning team members for contests, or taking part in open source projects. Can you kindly share other experiences?
I am a biochem post-doc and just tried projectnudge.com for this exact situation. The site appears to be beta testing social science collaborations. I was told my posting will appear on the site soon when they start releasing the science collaboration proposals.