GlobalSign gives free SSL certs to non-commercial free software projects (can a conference be free software?). I already bought a cheap 1 year cert, but I sent GlobalSign a message in case they’re handing out wildcard certs. The confirmation email is below, and I’ll keep you all updated.
Dear Samer Masterson,
Thank you for submitting your question to us. Case #01066343: “OpenSource SSL Request” has been created and GlobalSign Customer Service will respond to you shortly.
Customer Service Team GlobalSign
Your Case Request was :
EmacsConf is a non-commercial conference for the Emacs free software/open source text editor. We’re using emacsconf2015.org temporarily, and we’ll be switching to emacsconf.org as soon
as we have control of the url (in talks with the owner now).