Solution for "Secret Puzzle"

Stay on the line for the phone number in Puzzle 4. After the song ends, a reorder tone plays. Wait for about 1 minute of reorder tone, then a voice comes on that says "The answer to puzzle 8 is worms".

There were hints placed in the CSS of the website:

/********************************************************************
 * Hint for Puzzle 8                                                *
 * =================                                                *
 *                                                                  *
 * Stick around for a while. The answer may be at a seemingly       *
 * dead end.                                                        *
 ********************************************************************/

and:

/* Time travellers are sneaky!
 * ........ this is not the answer .............
 * ................. just another hint ......... */

Finally, there was a hint sent out in the "24-hours remaining" email:

Patience is a virtue. Be patient and the answer will come to you.