It is possible that a thread like this exists, but we all hear great songs in commercials every once in awhile, and always wonder what they are. We all also hear a song, and know we've heard it before in some commercial or TV show, and can never remember.
I sent a friend "The Other Side of Mt. Heart Attack" by Liars recently and he swears he's heard it on a show or commercial and wanted me to ask about it, so now we can have a thread for all questions of this nature, should anyone have any.