Game Jam Resources

Sounds and Music
Kevin MacLeod – Hundreds of music tracks in a wide range of genres (CC-BY)
Freesound – Lots of creative commons sound effects and music.
Open Game Art – Art, music, and models. Under a vareity of licenses, so pay attention.
Green Island soundtrack by Alpha Secret Base

Sounds and Music
http://www.bfxr.net/ -

Images and artwork

CC Search – Search several media and image sites for creative commons content.
OpenGameArt – Art, music, and models. Under a vareity of licenses, so pay attention.
Fonts

Font Squirrel – Lots of awesome fonts with a free commercial licenses.

Random stuff
Alpha Secret Base (Japanese only) – Games, music, art, etc… The content is under a BSD license according to this notice unless a more specific license is included on a page / in a file.