Mars and Stars weekend At noon on July 4, NASA's Pathfinder lands on Mars. Today through July 6, the Burke-Baker Planetarium celebrates with a slew of Red Planet activities for your little space cadet. Among them: the new Destination Mars! planetarium show; a meteorite you can touch; Pathfinder live feeds from NASA-TV; and a 3-D display of Mars volcanoes and canyons. Museum hours 9 a.m.6 p.m. today; planetarium show every hour, 11 a.m.6 p.m. At the Burke-Baker Planetarium, Houston Museum of Natural Science, One Hermann Circle Drive (in Hermann Park), 639-IMAX, www.hmns.org. $3 adults, $2 kids under 12.
A lawn chair and 45 weather balloons A very American story: In 1982, California truck driver Larry Walters attached 45 weather balloons to a lawn chair and ascended to 16,000 feet, where he was spotted by passing jet pilots. Cold and scared, he shot some of the balloons with his pellet gun, then crashed into a power line, briefly blacking out part of Long Beach. "It was something I had to do," he told reporters. Afterward, he went on the Letterman show and for a while made a living as a motivational speaker. Then, 11 years after his flight, he committed suicide. Tonight 25-year-old Richie Budd salutes Walters. Tethered to the ground by a shoestring, Budd will sit in a balloon-boosted lawn chair, sipping beer and watching Fourth of July fireworks. Gallery patrons (this is performance art) can watch Budd both from the rooftop and on closed-circuit TV. God bless the U.S.A. 7 p.m.midnight; in case of heavy rain, the takeoff will be rescheduled for Saturday, July 5. Revolution Summer, 1215 Marconi, 521-7564. Free.
Watermelon Fest and Ice Cream Crank-Off Galveston's Moody Gardens adds Fourth of July bonuses to its usual attractions (you remember those: IMAX, the Rain Forest Pyramid, the space-related Discovery Pyramid, the kiddie-pool nirvana of Palm Beach). This afternoon, ice-cream aficionados will compete to produce the finest of frozen treats; visitors will get to sample, and celebrity judges will decide who wins a trip to Washington, D.C. Flags are free to kids, big slices of watermelon will go for $1, and there'll be sack races, seed-spitting contests and other silly old-fashioned games. Plants will be sold for $2$10; all proceeds will benefit Hope Therapy, which allows people with disabilities to work with horses and plants. At 6 p.m., Dr. Ken Dye's Concert Band plays patriotic tunes -- leaving time for you to grab dinner and wander down to the Strand to watch Galveston's fireworks (the show starts at 9:15 p.m., around 37th Street). The Watermelon Fest and Ice Cream Crank-Off runs 3 to 7 p.m. Moody Gardens, One Hope Boulevard, Galveston, (800) 582-4673. Free to attend the fest; other Moody Gardens attractions cost $6 each.
Houston Symphony As always, the Symphony provides a patriotic prelude to fireworks. Tonight's outdoor program, conducted by Stephen Stein, includes all the old standbys: "The Star-Spangled Banner," "Stars and Stripes Forever" and "The 1812 Overture," complete with cannons. 8:30 p.m. Miller Outdoor Theatre, Hermann Park, 520-3290. Free.
AstroWorld fireworks Yes, you can see these pyrotechnics from all over town -- but the very best viewing, says a Six Flags AstroWorld spokesman, is from AstroWorld's Southern Star Amphitheatre. And what more American way to spend a day than riding roller coasters, eating hot dogs and drinking overpriced Cokes? Park opens at 10 a.m. Fireworks at 10 p.m. AstroWorld, 9001 Kirby, 799-1234. $31.95, 48" and taller; $20.95, under 48 inches; two and under, free.
Houston Freedom Festival The outdoor mega-party focuses mostly on music: Miss Frances and the Rhythm Fish play at 4:45 p.m.; Dale Nowak and the Young Country Band at 5:45; the Norma Zenteno Band at 7; and country star Mark Chesnutt at 8:15. Fireworks begin at 9:45, and the traffic jam starts soon after. In Buffalo Bayou Park; parking available in the Theater District parking garage. Free, but this year a pass is required. Get it at your neighborhood Diamond Shamrock or Stop N Go.
Tri-Star Collectors Show Nostalgic for the era before baseball cards became big business? Oddly, so is Tri-Star, which bills itself as "America's Premier Producer of Sports Collectible Shows!" Today's blowout, held at a soulless hotel rather than a soulless convention center, is supposed to "turn back the clock to the golden years of the hobby, when shows had more of a local, intimate feel." Big-name athletes (NFL running backs Emmitt Smith and Thurman Thomas, as well as the Rockets' Eddie Johnson) will sign autographs for a price. And hometown up-and-comers (Rockets Othella Harrington and Randy Livingston, Astros Billy Wagner and Brad Ausmus) will sign for free -- just like in the good old days. 10 a.m.5 p.m. today; Sunday 10 a.m.4 p.m. At the Ramada Astrodome Hotel and Convention Center, 2100 South Braeswood (at Braeswood). To find out who's signing when, or to buy advance tickets, call 840-7827.