The whole of Get Involved is a link to Opportunities.

I don't understand.

This problem appears to be specific to Firefox (I tested in Chrome, and the problem isn't there).

Some of the links have expanded and overlay the whole page, so any click anywhere* within the page is a click on that link. Specifically, links with the coverall class in the right hand column cover the entire page (which actually means the page always directs to the link corresponding to the very last box i.e. Visiting Fellows for "About" and Opportunities for "Get Involved").

The problem is due to the fact that boxes in the left hand column have some extra CSS that includes position: relative, while those on the right don't. Adding this fixes the problem.

*Except on the links in the title bar and footer.