And he's off and riding. Cusack has a home in Los Angeles, but when you're from Chicago, you're a Chicagoan until the day you die. He has a place downtown, and on his first day or two back, he usually wants to see everything at once.

"I'll ride up and down the waterfront, go by Navy Pier, then all the way down the public park toward Montrose," he says, ticking off a multiday biking itinerary. "You can go all the way up and down Lake Shore Drive. There are parks all over there. Then you can go through the city and all of its different neighborhoods - Wrigleyville and near Halsted, everywhere. You can go up toward the South Side, toward Millennium Park, to the Shedd Aquarium and Soldier Field, through Chinatown, and all the way back through the city to the Loop, and then through downtown."

He could practically bike through Chicago­ blindfolded. "I know the city inside and out," he says. "I don't think there's an area I haven't been to."

Then he begins directing me: "There is a tour where you can go up and down the river and see the architecture there - it's just out of control."

He's talking about a boat tour called Chicago from the Lake, which hits the highlights of Chicago architecture. But Cusack prefers the bike to the boat. "You go past the Wrigley Building," he says of the circa-1921 terra-cotta-clad edifice that's known as the gateway to the Magnificent Mile, one of the greatest shopping streets on earth.

He'll bike by the city's landmarks, starting at the Marshall Field's building, where his parents used to take him to see the big tree at Christmas. Then there's the Sears Tower and the John Hancock Center, where Cusack will jump off the bike and hop into an elevator, arriving at the top of the Hancock, where a diorama of the history of Chicago competes with the heavenly view. "The John Hancock is great because you can see the whole city from all the way around," he says.

Back on the street, he heads into Bucktown, once a scruffy quarter named for the immigrant families who kept goats in their yards and now Chicago's hottest neighborhood. Cusack fans would recognize it from his 2000 movie High Fidelity, in which John starred with his sister Joan as a Chicago record-store owner charting his top five romantic breakups.

"You can take your bike through Bucktown, which is terrific," Cusack says. "Just a cool area with lots of great coffee shops and clubs and restaurants. We shot all over there for High Fidelity. It's where Double Door [a live-music venue] is. There are great record stores in Bucktown. Tiny little record stores like the one in High Fidelity. They are all over. You can also find great funky art and stuff like that."

When the lunch hour looms, Cusack bikes to Leo's. "Leo's Lunchroom," he says. "That's a great little place for lunch, a tiny little diner, down on … I can't remember where it is [in Bucktown]. I know how to get there on a bike."