'Tis a bit pricey ($500!), but this year's MeshForum (May 7-8) has opened the doors to general public registration.
Speakers include Manual Lima of VisualComplexity, and tons of academic, business, and government types.
So if you want to learn about the latest in Network Science, and get a chance to explore the great city of Chicago, give 'em a call. Deadline for early registration is March 1st.
Addendum: Shannon notes in the comments that scholarships and discounts may be available for those of diminished means (e.g., grad students).