1. Rocket Launch - Cocoa Beach, Florida
Jump-start your adventure by observing a NASA shuttle or rocket launch on Florida's "Space Coast." Locals celebrate launch day at Cocoa Beach Pier, though the better view is from Space View Park in Titusville, 30 miles away. Watching is free-and to see a launch is to remember it forever.
2. Flight Check - Kitty Hawk, North Carolina
As you greet the sunrise on the dunes, you'll have the same Atlantic Ocean view Orville and Wilbur Wright enjoyed the morning they pioneered flight. Admission to the museum at Kitty Hawk is free for those 15 and under, and the beach is open to all.
3. Citizenship Ceremony - Charlottesville, Virginia
Every Independence Day, an event guaranteed to inspire lumps in the throat and warm feelings of national pride takes place at Thomas Jefferson's home. Since 1963, the highlight of Monticello's July 4th festivities has been the swearing in of new American citizens. Over the years, some of the most poignant sentiments have come from foreign-born guest speakers (architect I. M. Pei, Secretary of State Madeleine Albright). Filmmaker Ken Burns will speak at this year's event.
4. Cemetery Walk - Arlington, Virginia
Veterans of every armed conflict from the Revolutionary War to the war in Iraq are buried at Arlington National Cemetery, as are astronauts, explorers, Supreme Court Justices, and Presidents. John F. Kennedy, his wife, Jacqueline, and brother Robert are buried near the Tomb of the Unknowns. At the top of the hill is Arlington House, Robert E. Lee's former plantation, plus a panoramic view of Washington, D.C.
5. Gallery Tour - Washington, D.C.
Monuments and museums dot the capital, with free entry to almost all of them. Don't overlook one of the lesser-known showpieces: Part of the Smithsonian Institution, the National Portrait Gallery stands as visual testimony to American greatness, with images ranging from sports heroes to movie stars.
6. Panda Party - Washington, D.C.
Plenty of American cities have a zoo. Only four have giant pandas. On July 9, Tai Shan, the panda cub born to great fanfare at the National Zoo, celebrates his third birthday. To ensure a glimpse of the cub and his parents, arrive in the early morning or late afternoon, when pandas are most active.
7. 9/11 Memorial - Shanksville, Pennsylvania
On September 11, 2001, passengers on United Airlines Flight 93 tried to gain control of the plane. They lost that fight, and their lives, but saved many others. The memorial being built in the field where the jet crashed is not yet permanent, but your memories of the visit will be.
8. Afternoon in the Park - New York City
Central Park is full of free fun, with its walking paths, softball games, open-air concerts, and 21 children's playgrounds. The Central Park Conservancy offers basketball clinics on Thursdays and Saturdays for kids 9 to 17-no preregistration required. Admire the miniature remote-control sailboats on the pond, visit the Strawberry Fields memorial to John Lennon, or take in one of the many no-cost dance, theater, and film events run by Central Park SummerStage.
9. Ancestor Search - New York City
Forty percent of us trace our heritage to the immigrants who arrived through Ellis Island in New York Harbor. You'll pay a ferry charge to get there ($12; $10 for seniors; $5 for kids) but no fee to visit the Statue of Liberty or Ellis Island. At the American Family Immigration History Center, $5 lets you search the ships' records to discover when your ancestors arrived on these shores.
10. Campus Visit - Cambridge, Massachusetts
If you hit the Boston area on a Sunday, you can hear Reverend Professor Peter Gomes, known for his mellifluous voice, dry humor, and ecumenical sermons, preach at Harvard's Memorial Church. Nearby is Annenberg Hall, the freshman dining facility modeled after the great halls at Oxford and Cambridge. Henry James referred to this building as a "house of honor and hospitality." Contemporary visitors who peek through the doorway at the soaring ceilings and stained-glass windows will simply think, Hogwarts.
11. Bridge Crossing - Lexington and Concord, Massachusetts
The confrontation here between the minutemen and the British launched the Revolutionary War. On any July or August day, you can visit Concord's old North Bridge free of charge, cross the river where the Americans made their stand, and see Ralph Waldo Emerson's words etched in stone: "By the rude bridge that arched the flood,/Their flag to April's breeze unfurled,/ Here once the embattled farmers stood,/And fired the shot heard round the world."
12. Natural Wonder - Niagara Falls, New York
This phenomenon on New York's Canadian border has beguiled human beings for centuries. Native Americans called it Thundering Waters and believed its roaring sound emanated from the spiritual world. Legend claims they sent a maiden over the falls in a canoe. Since then, generations of daredevils have tested its power. Gaze from Prospect Point in Niagara Falls State Park. Admission is free, although parking costs $8.
13. Time Travel - Millersburg and Berlin, Ohio
In Amish Country, you can experience the past and future simultaneously: Sit in a coffee shop with free wireless access while watching a Mennonite or Amish family tie horses to a hitching post. Picnic in a field and see the hot-air balloons soar overhead, or attend the Amish Flea Market on Saturdays from April through December.
14. Urban Enjoyment - Chicago
A self-guided tour of this city's architecture, a bike ride along Lake Michigan, and tickets to The Oprah Winfrey Show-requested a year in advance-cost nothing. Thursday evenings, the Art Institute of Chicago and the Chicago Children's Museum waive their fees; the Museum of Contemporary Art is free on Tuesdays. There's never a charge for entry to the National Museum of Mexican Art or for the hourly water and light shows at Buckingham Fountain.
15. Cycling Spectacle - LeClaire, Iowa
Cheer on cyclists doing the RAGBRAI. The what? RAGBRAI (the Register's Annual Great Bicycle Ride Across Iowa) is a seven-day bike ride-not a race-that started 35 years ago as a challenge between two friends at the Des Moines Register. It costs $125 to ride but nothing to applaud the thousands of riders on the last day (this year, July 26) amid a giant party along the Mississippi River in LeClaire.
16. Mountain Picnic - Boulder, Colorado
As you drive into Boulder on U.S. Highway 36, the backdrop of the Rockies resembles a postcard of the Alps. Drive up Flagstaff Road, park your car, and walk a few yards to picnic tables amid the trees. After lunch, take every scrap with you. Littering is illegal everywhere in the States, but in Boulder it's also considered a sin.
17. Native History - Southwestern Montana
Head north, to Big Hole National Battlefield, on State Route 43. This site commemorates an event in U.S. history that's tempting to forget: the brutal treatment of the Nez Perce-the very people who helped Lewis and Clark on their expedition of discovery. The Park Service charges no admission to this site, which re-creates the Nez Perce village on the Big Hole River that was attacked at dawn on August 9, 1877.
18. Shopping Experience - Seattle
Downtown's Pike Place Market claims to be the nation's oldest continuously running farmers' market. Don't miss the fishmongers tossing salmon and other "flying" fish to clerks at the counter. You have to pay for your fish, of course, but not to see this cheerful ritual played out all day long.
19. Tree Gazing - Humboldt County, California
Don't miss a glimpse of the very tall trees in Redwood National Park on California's northern coast (Hyperion is the world's tallest, at 379 feet). These redwood ecosystems, which constitute America's rain forests, are hard to traverse but worth the effort.
20. Seals and Swimming - San Diego
At the southern end of the Golden State, in the village of La Jolla, you'll find a small, sandy cove called the Children's Pool. Its dilapidated seawall, constructed in the 1930s, still provides protection for swimmers, although recently it's been taken over by seals and sea lions who come here to rest. A court battle rages over whom the beach rightfully belongs to-people or seals-but regardless of who wins, both the water and creature watching are exhilarating.
21. Red Rock Climbing - Sedona, Arizona
Sedona's Coconino National Forest includes the famous red-rock formations Cathedral Rock and Bell Rock. Entry to the forest is free, but you'll pay $5 a day to leave your car. A few miles away, visit the Chapel of the Holy Cross. Designed by Marguerite Brunswig Staude, a student of Frank Lloyd Wright's, the modern structure complements the surrounding buttes and big blue skies.
22. Siege Site - San Antonio
Remember the Alamo? You will after visiting San Antonio and learning about its watershed moment in 1836. The rebels who defended this place died-but, spurred by the famous battle cry, the revolutionaries later won their fight for independence against a much larger Mexican army. The former mission and fort defended during the 13-day siege is now a museum.
23. Diamond discovery - Murfreesboro, Arkansas
This town claims the world's only public diamond mine. At Crater of Diamonds State Park, visitors can dig for the precious gems themselves. Since the first diamonds were discovered here, in 1906, more than 75,000 have been found. Entrance to the park is free, but digging costs $6.50 for teens and adults and $3.50 for kids. You keep any gems you unearth.
24. Music Appreciation - New Orleans
Much has changed in the aftermath of Hurricane Katrina, but the sights and sounds of the French Quarter remain eclectic. As you people-watch your way down Bourbon Street, listen for the mix of zydeco, rhythm and blues, and jazz that makes this city famous. Amid the revelers, you'll see groups of people who haven't forgotten that this is still a place very much in need: volunteers, taking a night off from building houses in the city or along the Gulf Coast.
25. Historical Hike - Mountain Park, Georgia
Your last stop could be the first stop on a very long hike: the Appalachian Trail. Even if you aren't up for the entire 2,100-mile trek, just setting foot on the famous footpath gives you bragging rights. Start at the beginning, 30 miles north of Atlanta, at Springer Mountain. Follow the well-trod trail into pristine areas of the Chattahoochee National Forest. Walk for a few hours and turn around-or plan ahead and take six months to hike all the way to Maine, a state you didn't get to visit on this trip. Maybe next year.