Live instances

Organizations

These are instances run by organizations, usually having registration limited to organization members:

• media.libreplanet.org -- The Free Software Foundation's photos and videos from talks and conferences.
• media.freesoftware.org -- Free Software Melbourne's archive of photos, audio and video from meet-up talks and Software Freedom Day presentations.

Family/Friends

Also, these sites are running MediaGoblin, but are for more limited audiences (family/friends of person who's running it, etc):

• isengaara.de -- IsengaaraP's mediahub for sharing eCantorix songs and コスプレ photos.

You can add your instance here, too!