BLASTS FROM THE PAST It’s a good week for nostalgia in the restaurant world. Now open is the Diner (44 Ninth Ave. at 14th Street, 212-627-2230 ), which evokes urban American eateries of the 1930s and 1940s. It is owned by Sergio and Mario Riva – who also own Candela – in partnership with Marc Packer, who owns Tao, Rue 57, Avra, and Balzano. Burgers and shakes, fried chicken, Mac and cheese, apple pie, and cheesecake are on offer until 4 a.m. Sunday through Wednesday, and until 6 a.m. Thursday, Friday, and Saturday.

Don’t try to stay for breakfast, though. That won’t be served until the first or second week of October. Also opening soon is the Soda Shop, within the Cosmopolitan Hotel (125 Chambers St. at West Broadway, 212-571-1100). Craig Bero, who also runs the Bespeckled Trout, owns the restaurant with partner Linda Donahue, whom he met over an egg cream at his West Village shop. The new TriBeCa operation is offering old-time candy and soda fountain-style drinks, house-made chocolates, and food in the style of diners circa the 1920s. But it will be modern New York, too: Among the optional additions to your double-decker grilled-cheese sandwich is prosciutto. And Mr. Bero is using his connections with suppliers that he has developed through the running of Grange Hall, Anglers & Writers, and Village Atelier to get top-notch greenmarket foodstuffs.

Dinner will be the restaurant’s usual lunchtime fare, plus one set meal, such as Thanksgiving-style roast turkey dinner with all the trimmings on Mondays.

TIME FOR OYSTERS The annual Oyster Frenzy at Grand Central Oyster Bar (Grand Central Terminal, 212-490-6650) is this Friday and Saturday. It starts Friday night with as many oysters as you can eat. You can choose from 15 varieties and 25 oyster-friendly wines, all for $80, including musical entertainment. Can’t make it on Friday? The same deal is on offer Saturday night. During the day on Saturday, starting at 1 p.m., professional oyster shuckers will compete for a $1,000 prize. Between rounds, the Oyster Bar will hold a “slurp off.” Whoever eats one of each of the 15 oyster varieties the fastest will win. Cooking demonstrations and samplings also will be held during the demonstration.

BROOKLYN BOYS If mini oyster po’ boy sandwiches are what get you started on a Saturday morning, visit Grand Army Plaza’s Greenmarket in Brooklyn (northwest entrance of Prospect Park, at Flatbush Avenue and Eastern Parkway) this Saturday for an oyster shucking demonstration by Aaron Bashy, chef-owner of the Minnow (442 9th St. at Seventh Avenue, 718-832-5500). The po’ boys will be available for a suggested donation of $2. Proceeds will go to United States Fund for UNICEF’s relief fund for the victims of Hurricane Katrina.

THE SHACK GOES ON Danny Meyer’s summertime burger and shake stand isn’t just for summer anymore. Shake Shack will be giving visitors to Madison Square Park a reason to wait in line for the entire autumn, too. It will stay open until December 23.And starting October 17, it will be serving breakfast from 7:30 to 11 a.m.

THE PARTY GOES ON SoHo has a new bar and lounge: Obivia (201 Lafayette St. at Kenmare Street,212-226-4904), which opened Monday. The focus is on drinks, with flights of liquor served in an ice block, 22 cocktails served in martini glasses, and 20 wines by the glass. Some food is served as well, including charcuterie and cheese plates, panini, and Mediterranean tapas.

Mr. Thorn is food editor of Nation’s Restaurant News. He can be reached atbthorn@nrn.com.