Across Northern Virginia, parents are gearing up for the last big party their children will have in high school.

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 drawings for new cars.

"We're always trying to find out what's the newest, what's the latest, what's the greatest," said Pam Rawlinson, co-chairman of the graduation night event for James Madison High School in Vienna.

The parties are held at local recreation centers and other venues, starting about 11 p.m. on the night of graduation and lasting until 5 a.m. Students are checked to make sure they are not bringing alcohol or drugs to the party and are strongly encouraged to stay through the night. Organizers work each year to find new and better games and prizes to make it 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.

Though schools publicize the events, the parties are a completely parent-run affair. Usually the parents start work soon after the school year begins, and many are there on graduation night as chaperons.

But the events are more than one final send-off for seniors. Since Project Graduation started, "We have not had any tragedies on the night of graduation," Rourke said. "It's been very, very successful." That is particularly important because graduation is seen as a rite of passage, and for some students that rite 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. Statistics show that 14 teenagers died in drunken driving-related accidents in 2001 -- in which they or a friend or an adult were driving drunk -- 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 schools commonly see 85 percent to 90 percent participation rates. This year, about 20,000 seniors are expected to take part.

Priscilla B. Godfrey, a Loudoun County School Board member and an organizer of Loudoun Valley High School's graduation party, said the school plans to start drumming up interest this week by hanging tags on seniors' lockers telling them about the event.

"I like to get half signed up as soon as possible, because then the rest will fall into line," Godfrey said.

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

Yorktown High School students in Arlington County will cruise on the Cherry Blossom, and the seniors have chosen a Las Vegas theme. A school Web page is updated regularly with the names of seniors who have signed up, so students can see if their friends are going. Already more than 120 seniors have bought tickets.

At George Mason High School in Falls Church, parents plan to give seniors a ride to the party in a yellow school bus -- the last bus ride of their school careers, said parent and graduation night co-chairman Renee Andrews.

"It's a night when kids are so vulnerable. It's a celebration, and it's protection," Andrews said. "We want to show them you don't need alcohol and drugs to have a good time."