Michael Sunder was lured away from his Thanksgiving dinner by a 40-inch television.

The 19-year-old and 41 million fellow bargain hunters, about ­17 percent of the population, were expected to forgo holiday traditions, if not the entire turkey, in search of bargains. Sunder, an Ellicott City native, parked in a lawn chair outside the Best Buy in Elkridge with six friends at 7 a.m. Thursday.

Retailers used to open at dawn Friday, slashing prices so low on flat-screens that who could resist? Then, just a few years ago, it was suddenly midnight, a kind of slumber party of shopping. Last year, Black Friday crept stealthily into Thursday, as the biggest big-box stores threw open their doors at 10 p.m. And this year, stores facing the dual challenge of a slow economic recovery and the proliferation of new online shopping tools have boldly invited themselves into the dinner hour — 8 p.m. — mingling some of the oldest of American rituals: giving thanks, eating turkey and hunting bargains.

Michelle Vanaelst typically shops on Black Friday, but she came out a day early this year by Wal-Mart discounts on pillows and mattress toppers. Her family held Thanksgiving dinner early so she and her cousin could get to the store on time.

“It’s not the typical Black Friday,” Vanaelst said. “I like the way it always used to be.”

Shopping on Thanksgiving is here to stay, and though many people are unhappy about it, consumers have only themselves to blame, the stores say. Just as much as we want to watch football, gather with family and succumb to tryptophan on Thanksgiving, more and more, we want to shop.

Rhonda Thompson sent her 10-year-old son to spend Thanksgiving with his grandparents this year so she could get to Wal-Mart in time for the sale on the PlayStation 3. But when she arrived at 6:30 p.m., the line was already too long and she knew there wouldn’t be any left.

The earlier start times are frustrating, Thompson said. “I think it’s unfair and unjust. It’s infringing on your quality time with your family,” she said.

The scene outside Washington area malls and shopping centers largely confirmed retailers’ predictions that consumers were willing to give up a family dinner — or at least dessert — for a deep discount. By about 4 p.m. Thursday, there was a line of more than a dozen people outside the Best Buy in Columbia Heights, which wouldn’t open until midnight. Many sat on milk crates, while a security guard looked out for line jumpers.

Saeed Yazdi was coaxed out for his first Black Friday line by a friend who convinced him it was the best way to get a new Apple computer. The computer, he said, is not available online at the cheaper price he needs.

“I do what I have to do, and there is no other way,” Yazdi, 48, said as he began his eight-hour wait for the store to open. “They don’t sell it online or I would do that. I think they want to bring the people here and make them tired. It’s veiled punishment.”

Minutes before the doors opened at 8 p.m., the line at the Toys R Us in Columbia stretched more than 100 people deep past the end of the shopping center’s sidewalk with cars still pulling into the parking lot. A store employee doled out gift bags stuffed with $30 worth of toys to the first families in line, one of many perks the toy store offered to coax shoppers away from the dinner table.

As the clock neared 8 p.m., an employee slid the store’s glass doors open. “You ready?” he asked the first shoppers in line. Then they flooded into the store, pushing empty carts waiting to be filled.

This weekend is a critical one for big-box retailers, which count on holiday sales for 40 percent of their revenue every year. As consumers continue to hold their purse strings tight, retailers are jockeying for a bigger portion of a shrinking retail pie and pulling out all the stops to draw in shoppers.

Still, the idea that shopping was encroaching on family fellowship rubs many people the wrong way. After Target announced it would open at 9 p.m. on Thanksgiving, employees launched an online petition urging the retailer to stay closed.

At about 8:30 p.m., protesters briefly gathered at a Wal-Mart to register their disapproval of the retailer’s labor practices. The protesters planned to visit two other Maryland Wal-Mart stores before midnight.

Inside, the atmosphere was much different. Instead of standing in one long line outside, shoppers lined up at various locations throughout the store. Large balloons were hung from the top of shelving indicating the discount item available: “iPad line starts here.”

Customers in the longest lines sought ways to stay comfortable. One woman in line for the Xbox co-opted a pink beanbag chair from the home furnishings section so she could have a seat. Another customer waiting for an iPad had set up a folding chair.

Throughout the store, customers grasped empty carts and idly tapped on smartphones as they held their position in line.

The earlier hours are helpful for moms such as Liz Mackay, who said she regularly shops for Black Friday deals to get “an early jump on being Santa Claus” for her two sons.

She left her children at home with her husband after Thanksgiving dinner this year. The Wal-Mart line for the Nintendo Wii was just her first stop. Toys R Us would be next. The earlier start time meant she should be home by dawn, when her family wakes up.

The intrusion into Thanksgiving may have reached its limit, some analysts say.

“Evening sales will absolutely continue — customers love it — but I think the sanctity of the day will continue to be protected,” said Kit Yarrow, head of the psychology department at Golden Gate University in San Francisco. “I really don’t think we’ll see stores opening much earlier than this.”

And the strategy might not be enough to secure the holiday sales boost that retailers are hoping for. The sales that stores racked up on Thanksgiving might eat into purchases that typically take place on Black Friday and the rest of the weekend.

Still, for retailers facing a tough holiday shopping season, it might be better to secure sales early rather than risk losing them to a competitor.

But this year’s big discounts left some shoppers disenchanted. Felicia Hammond, 51, arrived at the Best Buy in Elkridge at 10:30 p.m. Wednesday anticipating that the line would wrap around the corner, as it did last year.

Instead, she said, the crowds were much thinner this time around. She could have slept at home in bed and still managed to grab a spot in line Thursday afternoon that would have guaranteed her one of the limited number of products on sale.

An unemployed single mother, Hammond said the steep discounts allow her to buy big-ticket electronics that might otherwise be beyond her budget. “Needless to say, my family is not happy that I am missing being with them another year,” said Hammond, bundled up in a white winter coat and matching hat.

But it’s not over. About 81.5 million shoppers were expected to hold out for traditional Black Friday shopping, twice as many as were expected for Thanksgiving Day shopping, according to the International Council of Shopping Centers.

And some — such as Dawn Rivers, who arrived at the Fairfax Kmart on Thursday morning at 6:15 to buy, as she said, “whatever’s on sale”— were planning a shopping marathon that spanned both days.

Rivers, who lives in Vienna, said she planned to go to Wal-Mart, Macy’s and Bed, Bath & Beyond on Friday.

“Maybe I’ll go tonight, too,” she said. “It depends on how Thanksgiving goes.”

Tim Craig and Sarah Halzack contribued to this report.