Across the county, parents are gearing up for one of the last big parties their children will have as high school students.

All-night, alcohol-free graduation parties, which came to the area in the late 1980s as an alternative to riskier celebrations, have grown from modest events into elaborate affairs that include cruises on the Potomac, casino games for expensive prizes and even a drawing for a new car.

Already, 225 tickets have been sold for the Osbourn Park bash. If sales continue at that rate, there will have more partiers than ever before. The idea leaves organizer Anna Marie Morgan excited, if a tiny bit apprehensive.

"It's a problem I kind of like to have," she said. "My goal would be for all these kids to attend."

The events are often held at local recreation centers starting about 11 p.m. on the day of graduation and lasting until 5 a.m. Students are checked for alcohol and drugs and are strongly encouraged to stay through the night. Organizers work each year to find interesting games and prizes to make the parties an attractive destination.

"They don't exactly know what they're going to see or what they're going to do when they get there," said Marion Rourke, co-chairman of Northern Virginia Project Graduation, an umbrella group that helps parents at 44 area high schools organize the parties. Through the group, a lucky senior at each of this year's graduation night parties will have a chance to win a 2004 Ford Focus.

Although schools publicize the events, the parties are run entirely by parents. Usually the parents start organizing them soon after the school year begins, and many are there graduation night as chaperons. Parents who do not have seniors are strongly encouraged to get involved, so that they'll be prepared by the time their children graduate.

But the events are more than one final send-off. Since Project Graduation started, "we have not had any tragedies on the night of graduation," Rourke said. "It's been very, very successful." This is particularly important because graduation is seen as a rite of passage, and for some students that may involve drugs and alcohol, Rourke said.

Graduation is also a gateway to the summer months, and half of teenage drunken-driving deaths occur in June, July and August, said Kurt Gregory Erickson, executive director of the Washington Regional Alcohol Program.

Drunken driving in this area is on the rise, said Erickson, whose organization tracks incidents in the District and its suburbs. The latest statistics available show that 14 teenagers died in drunken-driving-related accidents in 2001, but the number rose to 21 in 2002. As of 2002, the area was in its fourth consecutive year of an increase in drunken-driving fatalities across all age groups.

"I frankly think that most people think this problem has been licked," Erickson said. "The complacency breeds a less-than-vigilant approach."

The after-graduation parties are considered one prevention effort. Rourke said this year, about 20,000 seniors throughout Northern Virginia are expected to take part.

Potomac High School seniors in Prince William County will take chartered buses to their graduation party destination, the Spirit of Washington cruise ship on the Potomac River. Organizer Terri Loveless said she uses her son as a way to keep track of what students want. "He's definitely getting excited," she said.

Teresa Sands, organizer of Hylton's party, said that the party is worth the months of planning.

"Graduation is an important time for these kids," Sands said. The party gives them a chance to enjoy the night, without the risk of alcohol or drugs.

"That's what we're promoting," Sands said. "There are other ways to celebrate."