Proceeds from tip jars and carnival-style games at the event will go to a nonprofit foundation the firefighters' union has set up. Conrad said the foundation likely would donate to college scholarships, fire education programs and charities.
The winner of a 50-50 drawing might collect as much as $50,000, he said.
The Bonanza Extravaganza will be May 12-14 at Hagerstown Speedway, west of Hagerstown.
Starting at noon, prizes will be given out on May 13 through drawings every five minutes. The drawing for the top prize - $100,000 - is scheduled to be shortly before 8 p.m.
The prize list includes seven Chevrolet cars and trucks, seven Harley-Davidson motorcycles, 30 guns, 38 cash awards, ATVs, trailers and personal watercrafts.
The Bonanza Extravaganza will have live music, vendors and other attractions. Beer will be sold to people at least 21 years old; a mug will cost $10, with free refills.
The union's break-even point for ticket sales is about 8,500, Conrad said. After that point, it has plans for selling the remaining 1,500.
"We expect to sell out," said John Murray, a firefighter on the event committee.
If fewer than 8,500 tickets are sold, the event will be canceled and all money will be refunded, the event rules say.
Hagerstown's firefighters union has helped Cumberland, Md., hold its own version of the Bonanza Extravaganza for four or five years.
"In 2003, we finally decided we wanted to try this ourselves," Conrad said.
The firefighters union originally planned the Bonanza Extravaganza for September 2005 at Fairgrounds Park, even though it might have required an estimated $100,000 or more in upgrades for the park.
But, Conrad said Monday, various logistical problems couldn't be solved, so the festival was postponed.
He said this year's event is gathering steam through an Internet site (www.iafflocal1605.com) that's getting 60 hits a day and through word of mouth.
The prize list has been a prime marketing device, "if we can get that in someone's hand," he said. Firefighters distributed thousands of fliers at a recent Harley-Davidson event in Pennsylvania; they got calls on the Bonanza hotlines before they were done, Conrad said.
Firefighters from New York, Connecticut and North Carolina are among those who have said they'll attend.
"We just sold four tickets to (a buyer in) Seattle," Conrad said.
Guests of ticket holders may attend for $20, but won't be eligible for prizes.