• Dog food, "given Mr. Phelps's well-known love for his British bulldog, Herman."
  • Bobblehead dolls
  • Acrylic paintings
  • Commemorative coins
  • Car rims (!!!)
  • Tuxedos
  • Swimwear (Speedo is an existing sponsor but contract is up)
  • Watches (Omega is an existing sponsor)
  • Credit cards (Visa is an existing sponsor)
  • Electronics (Phelps partnered with a Hong Kong-based MP3 player after the Athens games in 2004)

Even if Phelps makes his agent's estimate of $100 million, he will stake make in a lifetime what golfer Tiger Woods makes in a year, since Woods is constantly playing and, presumably, picked a sport of greater interest to the wealthy.

But Woods' groupies probably aren't half as hot or a tenth as numerous.