This is kind of ironic considering it's Adam Langley's website, but it appears his server is not indicating that it supports secure renegotiation, and apparently in the latest Firefox that's grounds to refuse a connection[1]. See:

https://www.ssllabs.com/ssltest/analyze.html?d=pond.imperial...

https://wiki.mozilla.org/Security:Renegotiation

https://community.qualys.com/blogs/securitylabs/2010/10/06/d...

If you set security.ssl.require_safe_negotiation to false in about:config you should be able to establish a connection.

[1] Edit: actually it's not; the parent poster had tweaked settings in about:config ;-)