Ethan Blum, 29, has given it a tremendous amount of thought, but the choice in the end is clear to him. He will wear his Chris Therien jersey to the Winter Classic.

This hockey game is such a momentous occasion that he's going all in. He'll even rock the bright orange sweatpants.

Blum is a third-generation Flyers fan. His father always loved the No. 6 in every Philadelphia sport — Julius Erving and Johnny Callison — and Blum has followed in the tradition of affection for No. 6, Therien's number.

Back in the 1990s, when Therien was a lumbering defenseman who worked hard but seldom scored, he rarely got the headlines, and nobody wore a Therien jersey. Stores didn't even sell them. This was last century, remember, and life was much more primitive.

So Blum had a Therien jersey custom-made.

And this game, the Winter Classic, an epic Philadelphia sports moment, just called out to him: Therien jersey.

Blum, who grew up in Lower Merion but now lives in New York City, considers himself "a true 4-for-4" Philadelphia sports fan. Slingbox and the Internet make him "feel like I never left." And often he is actually here. He arrives at all home Eagles games hours before kickoff, as soon as the lots open for tailgaters, and he cooks his breakfast and reads the papers.

He won't be quite so crazy for this 1 p.m. hockey game. He'll arrive by 9:30 a.m. — 10 at the latest. He bought his 8 a.m. Amtrak ticket from New York a month ago, and has been making plans with old friends, many of whom are going to the game.

Blum, who works in finance, could have and would have bought a ticket, but his good friend from childhood, Ben Coleman, works in advertising in New York, and he picked up two tickets.

"We really, really, lucked out and got two tickets for free from some company up here that probably doesn't deserve to have them in the first place," Blum said. "They should all be going to diehard fans. Luckily these two wound up in the right hands.

"You could have put me standing-room-only," he added, "or in a blimp a thousand feet up."

Why are fans like Blum so pumped?

Many cite similar reasons.

The Flyers themselves appear to be so excited. Many grew up playing on ponds in Canada, and this game, outdoors, on a rink set up inside Citizens Bank Park, harks back to their roots.

Many fans also relate on a personal level. Blum, for instance, didn't grow up playing hockey on local ponds, but he did play on local asphalt, every day after school on roller blades at Cynwyd Elementary and Bala Cynwyd Middle School.

Playing hockey in the Phillies ballpark — such cross-pollination — just stirs the blood of Philadelphia sports fans.

But each fan also has unique reasons for going.

Mike Spatacco, 26, of Bala Cynwyd, is taking his older brother and surprised him with a ticket as a Christmas gift. The brothers grew up going to Flyers games.

"It's always been something special for us," Mike said. His brother is moving to Los Angeles in January to pursue a career in acting and comedy. Mike felt the Winter Classic was the perfect hockey moment to share with his brother, worth $200 a ticket.

Lynne Sarota, 42, a construction project manager from Feasterville and a huge Flyers fan, is facing life-threatening surgery in February and decided to buy tickets as a special treat for herself. She and her friend will stop off at the Race Street Cafe before for brunch, and "the best Bloody Marys ever." For her, the perfect day.

Jim Metz, 45, a physician at the University of Pennsylvania who lives in Collingswood, loves going to games with his daughter, Isabela, 11. When she heard about the Winter Classic, she told him, "Dad, we just have to go."

Metz knows this will be a sports moment they will long remember, and for Christmas he bought her a Winter Classic jersey.

Tom Kiszka, 29, a mechanic from Aston, says "I've been a fan my whole life. My dad saw them win the Cup in the '70s. He raised me and my brothers as hockey fans."

His father and grandmother got season tickets in the early '80s, and Kiszka and his brothers share them today. Kiszka will tailgate with family and friends. He called the Winter Classic "the big game, probably and possibly a once-in-a-lifetime thing."

Blum said he's hoping the day will be about 30 degrees, with slight snow flurries to make it feel like winter.

"It's just two teams that you know from the get-go are going to be right at each other's throats, and the stands are going to be absolutely ballistic," he said. "I cannot wait. I've got goose bumps just talking about it."

Contact staff writer Michael Vitez at 215-854-5639, mvitez@phillynews.com, or @michaelvitez on Twitter.