The first episode with the character of Denny Duquette.
Lauren Tom and Jeffrey Dean Morgan appeared in multiple episodes of Supernatural (2005), though not in the same episodes.
Jennette McCurdy auditioned for the role of "Bex."
Speaking of song titles, not only the REM song, but there is an earlier song by Cole Porter, made famous by Artie Shaw, called Begin the Beguine. Both the REM song and this episode refer to that long ago song.