NEW YORK – With just minutes to go until deadline, the coders sit furiously typing, putting the finishing touches on their website. Brett Martin turns to his computer — the PowerPoint slides are almost done.

On the couch, a tiny dog buries his head into a blanket and shuts his eyes.

“Spanky’s the only one who got to sleep,” Martin says.

This group of nine entrepreneur hopefuls started less than two days ago with just an idea: an online planning and finance tool for small businesses called ProphetMargin. Now they have the website design, a business plan and a working database. And by the end of the evening, they’ll have a formal mentor and a meeting planned with investors.

Such is the pace of Startup Weekend, one of the final events of New York’s Internet Week, which ended Monday. Participants in the 48-hour marathon came in alone with an idea and left with like-minded partners and a fledgling business.

“It’s a testament to how much people can get done when they’re working on something they’re really excited about,” Martin said Monday, reflecting on his team’s accomplishments over the weekend.

ProphetMargin was one of 18 projects pitched Sunday night in the weekend’s final presentations. Other groups offered up plans for an app that would give users information about other people around them in public, a website to connect users with friends who need housesitters, an app allowing people to track the beers they drink, and an Internet platform to help adult entertainers build their brands.

The projects started as 60-second pitches Friday night. The 145 participants evaluated 57 suggestions and formed teams around the best ideas. Then they all got to work.

Usually, “you couldn’t create something like this without spending thousands of dollars,” Rob Steir marveled, looking around at his ProphetMargin teammates as they pushed through the final stretch. “We wouldn’t even know each other — we don’t know each other.”

Most teams gathered together people with varying specialties.

The group creating Data Dough — a service to help people sell their personal information to advertisers — included two software engineers, a graphic-design student, a computer-network manager, a Harvard Law School student, a new-media journalist and one person with a finance background.

In the end, the group’s work won it a prize — a mentorship from Noiz Ivy, an organization that supports entrepreneurs. — a platform that would allow users to display verified personal and professional achievements — and ProphetMargin won the same prize. A group creating a platform to help publishers market-test novels won a free month of shared working space.

And a representative from AOL Ventures said the company would meet with three groups and fund one of them. The finalists were, ProphetMargin and Deal Over Here — an app allowing people to buy unsold tickets just minutes before an event begins.

More than 500 teams have taken part in more than 100 startup weekends around the world over the last three years. Startup Weekend — itself a nonprofit startup run by three directors and a handful of volunteer facilitators — has gathered would-be entrepreneurs in cities from Copenhagen to Istanbul. It’s funded by a combination of sponsorships and entry fees. Participants usually pay less than $100 each.

And there’s no guarantee that any of the projects will live on beyond the weekend, only hope.