The Lotto ticket line crept forward from the shadowy depths of the Kettering Liquors & Cheese Shoppe in Largo.

It was a lunchtime crowd of two dozen secretaries and shoppers, homemakers and construction workers. But with each purchase yesterday of a Maryland state Lotto ticket -- or two, or 20 -- every customer underwent a somewhat giddy transformation.

"They're all potential millionaires now," said proprietor Ken Steele as a group of first-time players departed the liquor store with sheepish but gleeful grins.

In truth, they are potential multi-millionaires.

Tonight, at 7:55 p.m., the state will try to give away at least $12 million, the largest jackpot in the lottery's 17-month history. No one has won the Saturday night drawing of six numbers since March 16, when a comparatively measly $2.8 million was at stake.

Maryland Lottery Commission officials said players can buy tickets today up to 7:30 p.m.

Each week the jackpot has grown -- and so has the interest. On Friday alone, more than $1.6 million worth of tickets were sold at the 1,400 Maryland stores handling Lotto sales, according to state lottery spokesman Carlton Dotson. For the week, computerized sales of the $1 tickets total more than $5.5 million.

The lure of such a rich jackpot has brought out plenty of players who would otherwise disregard the weekly drawing.

"I've done this once before," said Marge McDonnell, who patiently stood in a Lotto line during her lunch break from Prince George's Community College. "I usually don't pay much attention to it, but $12 million sort of caught my eye."

Most people appeared undaunted by the astronomical odds; the chances of winning the jackpot are about one in two million.

"So what?" said Anne MacKinnon, after purchasing her first Lotto ticket. "If I don't play at all, my chances are zero in two million, right? Somebody's got to win, right?"

"And that's going to be me," said her friend, Debbie Myers, an Upper Marlboro office worker.

The old jackpot record, $5.5 million, was won on January 14, 1984, by Deloise Singletary, a 54-year-old nurse's aide who lived in a rented row house in Baltimore. With her winnings, Singletary has since bought a new three-bedroom home with a heated swimming pool and a Mercedes for herself and other cars for three of her four children. She also took her six grandchildren to Disney World in Florida for a week.

Until tonight's drawing, most ticket-holders will probably indulge in "What if?" fantasies. That sort of wishful thinking gave a festive air to the waiting crowds at Lotto sales outlets yesterday.

Myers, for example, would promptly hire a personal masseur, she said. Garland Franklin, a retired PEPCO employe, would buy new houses for all his children and a shiny blue Cadillac for himself. McDonnell would make cautious investments. Schoolteacher Charles Wood would buy his wife, Alice, "anything her little heart desires."

"The first thing I'd do," said Barbara Lindsay, a fast-food manager, "is buy myself a beautiful new house and then, I'd hide for a year."

Anthony Jackson, a traveling salesman, was just passing through Prince George's County yesterday afternoon on his way to his Hyattsville, Pa., home. He happened to hear an advertisement about the record lottery on his car radio and promptly zipped in to a Largo store and bought a dozen tickets.

"I could probably live very well" on the winnings," said Jackson, 34. "It would be just enough to allow me to live in the manner I am accustomed to, in my heart, but unable to afford."

Not everyone was touched with Lotto fever, however.

Wes Hite, 29, spent yesterday dispensing hundreds of tickets to millionaire-hopefuls at Largo Liquors. He remained steadfastly unmoved by the excitement.

"Me," he said, as he handed 20 tickets to a customer, "I'd rather drink my money or go out to dinner. I go for the sure thing."