Kathy Alsmeyer is all about saving lives. As a nurse at Shady Grove Hospital, Alsmeyer spends her days making sure patients are prepared for surgery. She spends her evenings making sure that the juniors and seniors at Rockville's Richard Montgomery High School are going to have a safe night of fun after tomorrow's prom.

Since the school year began, Alsmeyer, 47, and her trusty sidekick Jan Martin, both of Rockville, have spent five to eight hours a week planning the school's mammoth post-prom "Wild, Wild West" party.

At midnight tomorrow, just after the last dance at the prom (at the Holiday Inn Select in Bethesda), the school's PTA-sponsored after-prom party will begin at the Potomac Community Center. There, students will play until dawn. The concept: give them a safe, alcohol- and drug-free place to hang out and they'll be less likely to get into trouble.

It's a concept that works, said Meg Baker of Montgomery County Project Prom, who has tracked police reports over the years. "There have been no drug- or alcohol-related crashes at schools on prom nights [since we started]. . . . That's the reason for keeping this going," said Baker, 57, of Germantown.

She and Karen Bashir of Rockville have kept it going since 1992, when they established the group. Now, even though their children are pushing 30, they continue their volunteer efforts to make sure other people's teenagers are safe. They teach the county's PTAs how to host alcohol- and drug-free celebrations that teenagers will want to attend. Which is, of course, the trick.

At Richard Montgomery, volunteers apparently have found the magic formula to entice students to the post-prom, which will cost the school's PTA about $11,000. For the past few weeks, the line for tickets has wound through the lobby and up the stairs as students have used their lunch break to purchase 500 tickets.

Since party organizers realize that students have paid more than $75 a couple for prom tickets (not including all the accessories such as clothing, flowers and transportation) they've kept the post-prom ticket price at an affordable $5 per person. At Quince Orchard High School in Gaithersburg, the post-prom committee has done even better. Organizer Susan Weller, 47, of Gaithersburg said tickets are free if students buy tickets for the prom. Otherwise they cost $5 for juniors and seniors who want to go to the post-prom celebration only.

So what's the magic formula that entices 60 percent to 80 percent of the county's junior and senior high school students to attend their school's post-prom? Entertainment, free prizes and friends, all in one package and all night long.

"They have everything there," said 18-year-old Alex Perini, a Richard Montgomery senior from Derwood who is going to her third post-prom. "It's kids running around being crazy. It's the culminating event."

"I'm looking forward to the laser tag, the mechanical bull, the karaoke, too, even though I can't sing," said Kevin Morgan, 18, of Rockville, a Richard Montgomery senior getting ready for his second post-prom.

And, to keep the kids from leaving early, there are giveaways throughout the night, such as televisions and DVD players.

Hundreds of parents have spent thousands of hours worrying and scrambling to pull it all together. "It's a time when you don't want something to go wrong. It's important for them to be safe and have fun," said Martin, 47.

Said Richard Montgomery Principal Moreno Carrasco: "I commend the parents for their effort. It's remarkable."

Just as parents organize the parties as a way to keep their children out of trouble, some students say safety is a draw, too. "The witching hour is 2 to 5," said Richard Montgomery senior Elizabeth Mangan, 18. "Staying at the post-prom party is a way to be safe."

This year, all 23 Montgomery County high schools, in addition to 13 private schools, will hold an after-prom party. Two county police officers will be on duty at each of the schools, although many PTAs also hire additional security guards. Montgomery County police, the Rockville Police Department and the state police are part of a task force that has teamed up with Montgomery County Project Prom.

The post-prom celebrations are "absolutely making a difference," said Lucille Baur, public information officer for the Montgomery County police. "We know a majority of the kids go. If not for these parties there would be a lot more at home parties or hotel parties, and those are not good because they are not guaranteed to be alcohol free. If they consume, it can lead to alcohol poisoning, date rape, physical assault."

The parties, said Alsmeyer, are a team effort, with "a whole lot of cheerleading" from her group, which helps the post-prom committees with everything from post-prom philosophy to grant writing. School PTAs this year could receive up to $400 for party expenses through grants from the school system. The parties generally cost between $9,000 and $15,000.

To raise the money, some schools rely on parent and community donations while others hold fundraisers. At Quince Orchard, Weller said one cow, its "meadow muffins" and the football field helped the PTA raise $8,500. The group sold tickets and offered prizes to let people guess where on the field the cow would relieve itself.

The school's "Under the Boardwalk" post-prom party will take place on campus before dawn May 29.

Churchill High School in Potomac, which held its post-prom event early Saturday morning, mostly relied on parent donations. Spending about $13,000, the PTA transformed the school's gym, cafeteria and hallways into "Road Trip USA." For $5, partygoers "gambled" at a mock Las Vegas casino and bucked on a mechanical bull at a Midwest rodeo. In "Hollywood," they had their caricatures drawn and visited a removable-tattoo parlor.

For many seniors, the post-prom party is like the final curtain call. "It's probably going to be the last time I can be with [all my friends] before we go our separate ways," said Wootten High School senior Ethan Yaffe, 18, of Rockville. "It's a good chance to spend one long night together and have an amazing time."

Wootten will host its seniors-only Mardi Gras post-prom party on campus May 29.

Parent Eric Stone, 51, of Rockville, is in his third year as chairman of the event.

"I get drawn in every year because the party is all about community and the winning combination of safety and fun," said Stone.

Next week, read about the happenings at Richard Montgomery's post-prom party.

At top, Richard Montgomery High School post-prom coordinators Jan Martin, center, and Kathy Alsmeyer, right, count the day's ticket sales. Above, Richard Montgomery students line up at lunch to purchase tickets. At right, parent Diane Goleb sells tickets.