This is actually something a lot of swimmers do, and it's probably more psychological than anything. The goal is to make your head as smooth as possible and thus be able to move through the water faster. When races are decided by hundredths of a second, swimmers will try to get any advantage. Mostly, it simply feels more secure.
2 Erik Vendt, not Ryan Lochte, is his closest friend
Phelps and Lochte are pals -- they have a shared interest in music, women, life -- but they never talk about swimming. They're too competitive. Vendt, who trained with Phelps the last two years in Michigan, was one of his closest confidants during this difficult year that included uneven training and a broken wrist. They're also roommates during most meets.
3 He wears different suits for different events
When you watch Phelps swim the freestyle events, he usually wears the kind of Speedo LZR Racer that has straps over his shoulders and goes all the way down to his ankles. But when he swims an event where he needs to perform the butterfly stroke, he only wears the LZR Racer pants. Because so much shoulder motion is required for the fly, he feels more comfortable without something over his shoulders. You'll also see him in the relays immediately unzip his suit and pull it off his shoulders and down around his waist. It's not a vanity thing; it's because the suits are ridiculously tight and most swimmers want to unzip as soon as possible.
4 He rarely reads what's written about him
Phelps stopped reading about himself long ago. His coach Bob Bowman, on the other hand, reads everything. "I'm a big Google guy," Bowman says.
5 It's not always hip-hop on his iPod
This week Phelps has been listening to Lil Wayne, a rapper from New Orleans. He's also a big fan of artists such as Rick Ross, Young Jeezy and, of course, Jay-Z. But occasionally he'll mix things up and listen to some techno.
6 He spends a lot of time playing video games
He plays a lot of Madden, but he also plays Halo frequently as well. One week, he played so much Tiger Woods PGA Tour Golf on his Nintendo Wii, he came to practice with a sore shoulder, and Bowman said if that ever happened again he was taking the video game console away.
7 He knows how many strokes from one end of the pool to the other
When Phelps' goggles filled with water in the 200-meter butterfly Wednesday morning, he didn't freak out even though he couldn't see more than a few meters in front of him. He simply knew how many strokes it would take to get to the wall, and was counting in his head.
8 He falls asleep with the TV on
When you spend half your life in hotel rooms all around the world, the familiar sounds of ESPN or the Discovery Channel can provide some small measure of comfort.