Today is Black Friday, traditionally the first and most insane shopping day of the holiday season. After a night of giving thanks, devoted bargain hunters line up outside stores long before the sun rises.

Some shoppers these days head out even before the cranberry sauce is served.

While most businesses customarily close on Thanksgiving Day, a number of retailers got a head start on the busy shopping weekend.

Yesterday, the Sports Authority opened its doors from 9 a.m. to 3 p.m. at its stores in Queens and offered a 25% off coupon good only for Thanksgiving Day.

“It’s been pretty busy,” the manager of a Sports Authority in Woodside, Omi Maldonado, said yesterday. “Yes, there are people Christmas shopping, and there are a lot of people in the fishing aisle.” The footwear and outerwear sections also drew quite a few shoppers, she said.

Shoppers seeking to pick a few holiday gifts packed into the Sephora, a beauty and makeup retailer, on Columbus Avenue. The chain also kept open its Times Square store.

Some of the most eager shoppers were scheduled to leave on a bus to Central Valley, N.Y., from Penn Station at 11 p.m. last night to visit the premium outlet mall Woodbury Commons, which has kicked off a 24-hour “midnight madness” shopping frenzy.

More than 40 of the mall’s 220 stores, including Banana Republic, Coach,and Timberland, were scheduled to open their doors at midnight to throngs of shoppers and keep them open through midnight tonight. Some hotels offered special midnight madness weekend shopping packages.

Black Friday earned its nickname for the number of businesses that traditionally say their bottom lines zoom into the black from the red on the day after Thanksgiving. Retailers can rake in as much as 40% of their annual sales during the November-December selling season. This year, the shopping season is longer than usual, as Thanksgiving falls especially early, and retail forecasters say the outlook is better than expected.

“Recent consumer spending has surpassed our expectations, and we expect this momentum to continue through the holiday season,” the president and chief executive officer of the National Retail Federation, Tracy Mullin, said earlier this week. The trade organization increased its sales projection for the season to a gain of 6% over last year, up from an earlier forecast of a 5% rise.

While the early Black Friday may appeal to restless shoppers, it has irked some retailers, including P.C. Richard & Son, which ran a full-page advertisement in the Daily News yesterday decrying the switch as un-American.

“It is our opinion that retailers who choose to open on Thanksgiving Day show no respect to their employees’ families and are in total disrespect of family values in the United States of America,” the advertisement read.

An employee at the Sephora at the Time Warner mall at Columbus Circle, who asked to remain anonymous because of a company policy about speaking to the press, said she didn’t mind working.

“It’s money in my pocket when I need it most,” she said. “Now I go home, and the good thing is that because I was working, I didn’t have to cook.”

While shoppers seemed pleased to have the extra day, she said she didn’t expect Thursday would become the new Black Friday. She said Sephora was one of the few stores open in the mall aside from Williams-Sonoma.

“The tradition is that you stay home with your family, you’re not out shopping. We tried it, it was great for us. Because we’re in the heart of the parade, we had the traffic, but I don’t see another store surviving like us,” the employee said.

Most stores around the city did not buck tradition yesterday. Many will open as early as 6 this morning, offering deep discounts.