It's no longer Aspen's best-kept secret. Visitors have discovered what locals have always known—though the town's average temperature is 75 degrees, summertime is really hot.

More than 50 years of cultural events, from the nine-week Aspen Music Festival to Dance Aspen, have encouraged C.E.O.'s such as Michael Eisner and Les Wexner to build homes here. But perhaps no warm-weather happening is as much of a draw as the 4-year-old Aspen Ideas Festival, an offshoot of the Aspen Institute, which has been a gathering place for world leaders since 1949. This year the weeklong meeting of the minds takes place from June 30 to July 6. More than 250 speakers are expected, including Supreme Court justices, actors, generals, scientists, and leading journalists.

Tickets sell out a year in advance. But the size of the town (one square mile) means it's easy to run into speakers in the grocery store, a local shop, or a favorite restaurant. Here's where to:

Park the Plane: Aspen's Sardy Field is small, but it rates as one of the busiest airfields in the state. The "Aspen Air Force"—corporations such as General Mills, PepsiAmericas, Whirlpool, Johnson & Johnson, and Hilton Hotels—all use the private-aviation section of the airport, along with Bill Clinton, Rupert Murdoch, and many more. Commercial planes also fly into Aspen, but direct flights from cities other than Denver are few.

Rest Your Head: Ideas Festival speakers generally stay at the Aspen Meadows Resort, a Herbert Bayer-designed, Bauhaus-style hotel located on the Institute campus. If you can't get one of its 98 suites, try the Little Nell, Aspen's only five-star hotel; it has regular shuttles to the Institute, less than a mile away. The St. Regis is another hotel at which to see and be seen, particularly for those who can pay. If you can't, try the 35-room Annabelle Inn (formerly the Christmas Inn) right on Main Street, completely remodeled in 2005.

Dine Alfresco: Dining outside in summer is a good way to increase your visibility. Forget about privacy on favorite patios such as the one at Cache Cache, a hugely popular French bistro. Just next door, Campo de Fiori draws a beautiful crowd who pick at fish and authentic pastas. Or try Bill Clinton's favorite sushi spot, Matsuhisa, where he's often found holding court with owner Michael Goldberg and former Secretary of State Madeleine Albright.

Find a Meeting of the Minds: The place to find festival speakers is (appropriately) at Plato's bar and restaurant, right on the Institute campus. Not only does it have the best views of the Roaring Fork Valley, but you're bound to run into Mort Zuckerman or Institute head Walter Isaacson entertaining anyone from Colin Powell (a regular) to Katie Couric to Justice Stephen Breyer.

Party: The Crown family, which owns the Aspen Skiing Company among many other things, throws an annual Fourth of July party that is absolutely the place to be. At the top of Aspen Mountain, you'll find former United Airlines C.E.O. Gerald Greenwald and journalist and Harvard professor David Gergen mixing with local waiters and a wide variety of socialite types. If you can't snag an invite, try Belly Up (also owned by Michael Goldberg), a nightclub that during the Ideas Festival hosts seminars instead of rock bands. On a given night it might be Arlen Specter, Andrea Mitchell, or Thomas Friedman.

Go Local: Aspen's Fourth of July parade is quirky, funny, and sometimes out of control. Consider the year there was a golden retriever march and someone threw a bucket of balls into the fray. Each year, Leonard Lauder, president of Estée Lauder, and his family show up dressed in red, white, and blue. For outdoor recreation, hop a bike. The year Lance Armstrong came to the festival, he led a group of attendees on a ride up Independence Pass. Former Harvard president Larry Summers likes to sit on the lawn outside the music tent for a Sunday afternoon concert during the Aspen Music Festival.

Buy Cashmere and Cowboy Boots: Prada, Dior, Gucci—they all have Aspen outposts. Cashmere and frocks are found at the tiny boutiques of Nuages and Distractions, patronized by celebs such as Goldie Hawn. Everyone shows up at sports store Performance Ski, even in summer, when owner Lee Keating brings out sexy bikinis and surf lines. Queen Noor recently picked up a pair of cowboy boots at western shop Kemo Sabe. For the real bling, join Paula Zahn in picking up a pearl necklace by local jeweler Susan Walker at Cindy Griem Fine Jewels.