The mission? To “smoke” your target. The weapons? Squirt guns, water grenades, Super Soakers, and other water-based armaments.

New York City’s third installment of StreetWars, a nonlethal guerrilla-style sport, hits the alleys and sidewalks of all five boroughs next Monday and runs for three weeks. The August game is the first in which people can compete both as individual “assassins” and in assassin teams.

About 70 New Yorkers have already signed up to play the upcoming game, in which participants will be limited to 150. According to an organizer and cofounder, Franz Aliquo – known as Z0MB13 – the aspiring water snipers’ ages range from 13 to past 40, though the game is limited to those 18 and up.

“Right now, we have more women signed up than guys,” he said, “and lots of media, creative people, as well as professionals ranging from lawyers to social workers.”

Mr. Aliquo, 30, himself a securities lawyer, said he dreamed up StreetWars with a high school friend last summer when they were “just bored with life in general,” and about 75 warriors enlisted.

ZOMB13 found himself a target of Mayor Bloomberg’s yesterday, when a reporter asked the mayor at a question-and-answer session for his opinion of the StreetWars leader. Mr. Bloomberg said: “This guy could probably use some psychiatric help. If he calls one of the public hospitals, we’ll try to arrange that. It is not funny in this day and age. It may be funny for kids playing in the schoolyard. It’s not something that is appropriate on the streets of this city, given the world we live in.”

That the game is amusing to kids is one of its attractions, according to Gary “Black Lung” Kenney, 28, a self-described “banker-slash-actor” who helps Mr. Aliquo organize the event.

“Everyone’s always working and doing adult things and we forget all the cool things we used to do as kids,” Mr. Kenney said. “It’s about getting back to having fun.”

An unemployed bartender and DJ, Lola Belle, 31, was the winner of last July’s inaugural StreetWars.

“I did it because everyone on my Brooklyn kickball league was doing it,” she said. “A water-gun assassination game in the hottest month of the summer? Of course!”

She added: “I was completely paranoid the entire time and had no social life. … I would walk around the entire city with my water gun, crouching behind vans, getting curious, bemused looks from strangers.”

Ms. Belle said her winning strategy was to get up early, dress in professional wear, and read the newspaper in parks near her targets’ workplaces and homes.

“They never expected the pigtailed bartender to be up early wearing yuppie clothes,” she said.

Upon registering, participants receive “assassination packages” with the pictures, home, and work addresses, names, and contact information of the intended target or targets. If the target is a whole team, members may be killed off individually, but the team is not eliminated until the captain is shot.

“Safe zones” include the block around participants’ workplaces, subway cars, inside buses, and inside bars. Subway stations, bus stops, and restaurants with bars, however, are not off-limits.

According to Mr. Kenney, past StreetWars combatants have dressed up as delivery people and surprised people at their doors.

After a successful assassination attempt, the person killed gives his killer his envelope, and the victim’s target becomes the killer’s new prey. The process continues until a team or individual receives his own envelope.

Ben Eysselinck, 29, a database programmer whose nom de guerre is John P. Smith, is a member of the five-person Congress Occultus team. The team has various communication devices and purports to use Global Positioning System tools. Additionally, its “weaponry is all internally manufactured,” Mr. Eysselinck said, explaining, “We were unable to find appropriate items available on the international water weapons market.”

The winner or winners will take a cash prize – last year’s was $500 – and notice is also given for Last Man Standing, Most Kills, and Best Kill Story.