@ryanb Feel free to pick the ones you think would fit well, and tell me to create new issues for each one, or do so yourself.
Support other ways to login (facebook, twitter, google etc). omniauth should hopefully make that easy
Add share buttons for various services (twitter, facebook, g+, etc). Gets people advertising Railscasts more.
Add a 'Favourite' button, which stores the link between user and episiode and allows users to search/list favourites (as well as allows others to see someones favourites list).
Ability to 'vote up' episodes (for new users to find the most thrilling episodes)
Ability to 'vote up' comments (akin to stackoverflow)
Just jotting down thoughts.
@ryanb Feel free to pick the ones you think would fit well, and tell me to create new issues for each one, or do so yourself.