Smash Mouth - "Walkin' on the Sun"

Before downloading MP3s through iTunes, you would drive over to your local record store and purchase CDs.  In case you just wanted to buy one song instead of the full album, you'd buy a single.  Despite its name, singles contained more than one song.  Much like records, singles had a B-side.  In the case of Smash Mouth's "Walkin' on the Sun", the B-side was a song called "Sorry About Your Penis".