At game time, the temperature tumbled to 13 degrees below zero, with a minus-40 wind chill. Referee Norm Schachter's whistle froze to his lips. And the temperature kept dropping, but the fans staunchly remained, hunkered down in Lambeau Field, on New Year's Eve, 1967, for the coldest game in NFL history, a championship showdown forever famous as the Ice Bowl. Fans wore their clothing in layers, with, of course, warmers and ski masks and parkas; crowding together and clinging, many of them, to each other, they braved the glacial temperatures and remained to the dramatic end, a sellout crowd of 50,861.If that title game between the Cowboys and Packers were played today under the same arctic conditions, how many fans do you think would be at Lambeau and how many would stay at home instead to watch on their HDTVs?Sports -- nearly all of them, professional and college, no matter the shape or size of the ball, and from NASCAR to NCAA -- have seen their crowds shrink in recent years. For some, the decline continues. For others, attendance has virtually flatlined. Major League Baseball, for example, after three years of slipping numbers, saw a modest increase in attendance last year, 0.5 percent, but the total still fell 6 million shy of the 2007 record (79,447,312).Everyone agrees that the slumping economy is largely to blame. After all, the attendance downturn coincided, almost to the moment, with the economy's crashing through the guardrail and falling into the subprime sea.But is there more going on here? Did sports fans realize, perhaps to their surprise, that they could live quite happily, thank you, without attending all those games played by their local teams? Did fans who were able to wean themselves away from their beloved races and traditional tournaments discover a more satisfying option?Competing with homeBecause of economic necessity, which got an assist, in many cases, from high ticket prices, did fans decide to watch from home, where they didn't have to pay $50 to park, where they discovered they could actually see more of an event, thanks to their new HDTVs and to the variety of camera angles and replays, and where they enjoyed more comfort and more access to information and other media, not to mention a refrigerator full of cold beverages? Most important, will they be content to stay home?In January, on CBS' 60 Minutes, NFL commissioner Roger Goodell said the recession contributed to building a larger television audience for NFL games. And so in the future, he said, "because the experience is so great at home," the challenge facing the NFL is to get people to the stadiums."We've made the home experience so enjoyable and convenient that we're competing with ourselves, in effect," said Brian McCarthy, vice president of communications at the NFL.Professional football remains wildly popular. NFL games consistently sit at the top of the television ratings. More than 40 percent of the league revenue, which could approach $10 billion this year, derives from television. And so the NFL isn't as dependent as some sports on gate revenue.But because of slipping attendance, television blackouts have tripled since 2008, according to Business Insider, which asserts, in a headline: "The NFL Is Heading Towards An Attendance Crisis." Blackouts, of course, mean lost revenue. So there's a fragile interdependence, a crucial balancing that the NFL can maintain only by enticing, as Goodell said, more people to the stadiums.And so there's a peculiar irony: Television once attempted to provide a home audience the view from the stadium; and now stadiums must attempt to provide fans the comforts of home. Actually, though, stadiums have to provide much more.To do this, to compete with the at-home experience, stadiums and teams will try to offer more amenities, more media access and even more information. McCarthy said Cowboys Stadium, with its galleries and its mammoth video boards, has become an exemplar.NFL teams, he said, are also looking at making FanVision available. FanVision is a hand-held device that could provide access to other games, highlights and enhanced statistical information.Attendance stagnatesAs with MLB, NFL attendance has flatlined. After three years of declines, average attendance at NFL games increased 0.6 percent last year to 67,394. But alarms continued to sound. The Cincinnati Bengals sold out only two games. Season ticket sales for the Dolphins, The Miami Herald reported, fell to the lowest level in 28 years. Tampa Bay drew its largest "home" crowd -- 76,981 -- in London. And for the season, according to Rick Gosselin of The Dallas Morning News, more than 1.8 million seats were unfilled at NFL stadiums.Local teams, however, seem largely insulated from the trends. The Cowboys' home attendance has slipped slightly each of the last two years, but that's a predictable decline after the opening of the new stadium in 2009. The Cowboys have led the NFL in attendance each of the last three years. Last season, the Cowboys averaged 85,512 for every home game; no other team averaged more than 80,000.On their way to another American League pennant, the Texas Rangers last year set a franchise record with 2,946,949 in attendance. And since Dec. 15, 2001, after Friday's regular-season home finale, the Mavericks have sold out 432 regular-season games, best in the NBA, plus 58 playoff games.Winning, which reflects a quality product, certainly contributes to the strong local attendance. But, perhaps more than anything, as Mavericks owner Mark Cuban said in an e-mail, "North Texas has amazing sports fans."Elsewhere, though, attendance has not necessarily been so robust. More than 70 Division I men's basketball programs, or about 20 percent, have seen attendance drop at least 20 percent over the last four seasons, according to The Chronicle of Higher Education. Chris Fuller, senior associate athletics director at the University of Tennessee, includes television coverage that's "wildly saturated" among the reasons for the decline.Last year, total attendance for Division I football fell about 1.2 percent from the previous season, to 37,411,795, for an average of 46,074 fans for each regular-season game. That's the lowest average since 2005.Draining the CupFor many years, NASCAR's big-event attendance was the envy of the sporting world. But even NASCAR has felt the attendance crunch.The Bristol Motor Speedway in Tennessee seats 158,000. For the recent Sprint Cup race at Bristol, attendance was listed at 102,000, but, according to an Associated Press story, "the grandstand appeared to be roughly half-full."About 159,200 saw Greg Biffle beat Jimmie Johnson to the checkered flag last weekend in the Sprint Cup race at the Texas Motor Speedway. But while that's still a throng, it doesn't compare to the TMS record crowd of 212,585."We've seen our declines, but the last couple of years," said TMS president Eddie Gossage, "our attendance has been flat. For us, the declines coincided exactly with the sluggish economy. It was like somebody flipped a light switch."NASCAR tickets are relatively inexpensive. For as little as $20, you can see a race at the TMS. And TMS doesn't burden fans with the baggage of ancillary expenses -- "I'll never charge for general parking," Gossage said. But NASCAR has been hit especially hard, he said, by the rising price of gasoline since most fans travel a significant distance to attend.A sense of communityAnd although auto racing doesn't seem to be in competition with its own televised product, or at least not to an NFL degree, many speedways, Gossage said, are improving amenities and enhancing the experience of attending an event, just to keep pace with modernity. The Charlotte Motor Speedway, for example, has installed the largest HD video board in the country. (Yes, larger than the one at Cowboys Stadium, which actually has one on each side of the field.)But a televised race, Gossage said, could never replace the excitement of the actual thing. "The noises, the smells -- there's nothing like a live event," he said. "I truly believe that. .. And there's a sense of community among the fans, the relationships that develop -- it's all part of the experience."He might be right.Why do we watch sports after all? Why do we attend games, and races and tournaments? And why is that every culture has its favorite sports, from buzkashi to soccer?Reasons are numerous, of course, but Bruce Ogilvie, who's regarded as the father of sports psychology, years ago found perhaps the best explanation. Sports, he said, provide a sense of social meaning and purpose. They foster, in other words, a sense of community, and that's something that not even an HDTV can fully replicate.Would more than 50,000 attend the NFL title game if it were played, as it was in 1967, in arctic conditions? That's impossible to answer, of course. But it's quite possible that even more than 50,000 would attend. After all, Lambeau has increased its capacity to 73,128.