Some people (like me) don’t like games. Game mechanics-driven “check in” media like Foursquare, GoWalla, Loopt and BrightKite mostly leave them cold.

But what if check-ins triggered group buying discounts? That’s the concept behind GroupTabs, a new service launching in New York City next week. The idea is that offers could be floated on smartphones with a one- or two-hour window, and users can check in at the location. When enough people arrived, the discount (“20% off Wine Bar Purchases”) would kick in. The location pays a fee for the promotion if it reaches its threshold.

Led by former Citysearch sales exec Zane Friedman, GroupTabs began development in April. It has adopted Foursquare’s open API for check-ins, and plans to work with other check-in systems as well. One modification it has made is that it requires check-ins to be made at the location: Foursquare lets you do it all from your home or other locations.

“We give people a reason to try LBS [location-based services],” says mobile vet Josh Malin, who is part of the three-person start-up team. “Immediacy determines what they’re doing. They are not in it for the badge.”

Malin says the site will begin with one deal a day, and maybe add several deals a day after it starts adding some volume. He anticipates that the deals will be much smaller than Groupon-like deals, since they’ll mostly be tailored to bars and restaurants. Average deals might have 20 or 30 buyers. When New York is fully developed, additional markets may be pursued, perhaps up or down the East Coast, or San Francisco.

GroupTabs will obviously be limited to busy metro areas. Not many suburban areas will have 30 people ready to buy a drink down the street when they are gassing up or whatever.