June 21 is our "longest day" in the northern hemisphere, with longest hours of daylight; it also marks the official beginning of summer and many places celebrate. (If you're looking for "Summer Solstice" info about the tilt of the earth's axis and earth's revolution around the sun, detour to a Summer Solstice explanation about "our wonky planet".)
Summer Solstice rituals date back to ancient times; but the items below are all general come-one-come-all celebrations with no religious tone. Note that some events -- such as parades-- may be celebrated on a weekend, not the actual summer solstice day!
Summer Solstice Celebrations
Alaska - Summer Solstice Celebrations
Top billing goes to places with festivities under the 24-hour sun, and it's no surprise that in Alaska many cities and towns celebrate the Summer Solstice.
Yellowknife Summer Solstice Festival
Also "way up north", the capital of Canada's Northwest Territories has a multi-day Summer Solstice festival, with music, and face-painting and other fun for kids.
Summer Solstice in Scandinavia
In other Lands of the Midnight Sun: "Midsummer's Eve" is hugely popular in Scandinavia (and in Sweden, it's actually a national holiday.) About.com's Guide for Scandinavia for Visitors overviews the occasion in several countries. In Norway, for example, bonfires are a tradition; visitors to Oslo can simply join in around a bonfire near their hotel.
Moving to celebrations in lower latitudes... Scroll down for New York, Californa, and more. But first:
England: Stonehenge and Glastonbury
Mysterious, mythic Stonehenge is deeply associated with the solstices; and people do observe the Summer Solstice there. (See more about Summer Solstice at Stonehenge.) For a festival, however, try Glastonbury: known for legendary associations with King Arthur and the Holy Grail, Glastonbury has a Sunrise Celebration (--note: dates are early, May 29 to June 1 2008--), and a Festival of Contemporary Performing Arts that runs over the summer solstice date.
NYC: Times Square Summer Solstice
In New York City's tourist hotspot Times Square, featured activity on the summer solstice day is (would you have guessed this?) a free yoga-fest. Also, check for festivities organized by New York City Parks, such as this one in Queens: art-making, entertainment, face-painting, and more, at Socrates Sculpture park. (2007 info.)
Also in New York, (the city that just has to have everything) is "Manhattanhenge": just as Stonehenge has the summer solstice when the sun and the stones align just right, Manhattan too has magic moments when the sun "sets in exact alignment with the Manhattan grid, fully illuminating every single cross-street for the last fifteen minutes of daylight." Read about these interesting occurances (in May and July), described by Dr. Neil deGrasse Tyson, director of the Hayden Planetarium at the Museum of Natural History.
Boston: SummersDay Revels
A free 3-day event, June 20 to June 22, with music and dance performances, annual Summer Street Solstice Art Celebration, and more.
Boston Children's Museum
This Museum has an annual "Summer Revels" event, celebrating the first day of summer; 2007 had a free performance at the Museum’s new Children’s Wharf Park, featuring The Revels’ 40-member touring ensemble of adults and kids.
WI: Green Lake 10th Annual Summer Solstice Celebration
A day-long party with Summer Solstice "Bed Races", town-wide pajama party, Medallion Hunt in a 4-block radius, entertainment. Green Lake is within an 1-1/2 drive of Wisconsin's major cities, 3-hour drive from Chicago, and has lake recreation, hiking, etc.
CA: Summer Solstice in Los Angeles
A round-up of events, including Summer Solstice at Haramokngna American Indian Cultural Center, and Summer SOULstice Festival with kid-friendly activities such as scavenger hunt, pony rides.
CA: Los Angeles
For 25 years, the California Traditional Music Society has put on The Summer Solstice Folk Music, Dance and Storytelling Festival, with musicians, dancers, singers, and storytellers fom around the world. However, the 26th annual event has been postponed until 2009.
CA: Santa Barbara Summer Solstice Parade
This city between LA and San Francisco has a parade and a two-day festival; children's area with storytellers, musicians, air bouncer, face-painting, free art projects.
WA: Fremont Summer Solstice Parade
Started in the late 80's in this Seattle neighborhood, this Parade is now a "citywide community art parade". Anyone can join in the parade, or picnic afterward in a park, with music and food.

