*Dewey Music, an interface for much more easily browsing the Internet Archive's vast free collection of music (if you're a fan of live recordings, here's the mother lode). I could spend hours just looking up all of the genres on the "browse" page
*American English Dialect Recordings--a collection from the Center for Applied Linguistics that features 118 hours of North American accents
*RapGenius, a growing archive of rap songs with allusions and potentially unfamiliar slang explained (and sometimes, less usefully, just commented on)
*"Even Isolated Cultures Understand Emotions Conveyed by Western Music"--a post at Cognitive Daily, and a finding that somehow disappoints me
*"Linguistics Challenge" Puzzles--fun set of linguistics puzzles to work through
*Cover Lay Down, a music (and mp3) blog devoted to "folk covers of familiar songs, [and] reimagined versions of folk songs"