One of the hallmarks of the Pittsburgh Steelers dynasty of the 1970s, a stretch that produced four Super Bowl championships in six seasons, was that the powerful team almost never lost a game it was supposed to win.

During the four Super Bowl seasons -- '74, '75, '78 and '79 -- the Steelers amazingly dropped just one game to a club that had a losing record when the two teams played. It was, for sure, an unparalleled streak of consistency for a Pittsburgh team that did not permit the term "upset" in its vocabulary.

SIX POSSIBLE "TRAP" GAMES

1. Seattle at San Francisco (Dec. 1): On paper, a mismatch, but the 49ers weren't supposed to lose to a decimated Philadelphia bunch on Monday night and looked like they were coming apart at the seams. The Seahawks aren't likely to forget the "Sharpie" incident, involving Terrell Owens, from the teams' first meeting on Oct. 14. 2. Chicago at Green Bay (Dec. 1): Sure, the Bears are as decimated as any team in the league and they've lost four of the last five to the Packers in the NFL's longest and most storied series. But the Packers are hurting on the offensive and defensive lines, Brett Favre has thrown seven interceptions in Green Bay's two straight losses, and the Bears would love nothing better than to salvage some pride with an upset victory. 3. New Orleans at Baltimore (Dec. 8): As it demonstrated against Tennessee last weekend, the youthful Ravens defense is still solid enough to shut down good teams, even without middle linebacker Ray Lewis in the lineup. One added subplot: Ravens quarterback Jeff Blake isn't happy about the way he was treated when he played for the Saints and he's got a long memory. 4. Washington at Philadelphia (Dec. 15): Hey, it's the Redskins and Eagles. 'Nuff said, right? 5. Philadelphia at Dallas (Dec. 21): Old rivals who typically play close games that are usually decided in the final quarter. The Eagles dominated the Pokes in the first meeting, ripping them 44-13 in September, but who knows who will be playing quarterback for Philadelphia this time? 6. Tennessee at Houston (Dec. 29): If you're Bud Adams, the Tennessee owner who yanked his team out of Houston, you might want to consider a disguise for this contest. At least among the fans, the emotions will run high, and Texans coach Dom Capers usually has his team ready to compete. — Len Pasquarelli

Back "in the day," there was no surer wager than the Steelers matching up with an obviously inferior opponent. The Steelers usually took no prisoners because, in large part, they took no opponent for granted. Every game was viewed as a test of manhood and Pittsburgh characteristically proved it had more testosterone than the guys on the opposite sideline.

"We feared no one but we feared everyone … or rather we respected them all," said Hall of Fame cornerback Mel Blount. "That was the way (coach) Chuck (Noll) taught us. For us, every game was a test, and we almost never let down our guard. I mean, we took care of business, week in and week out."

Of course, the Steelers' reign of terror commenced nearly two full decades before the NFL instituted a salary cap and free agency, and it was markedly easier to maintain a roster stocked with superstars on both sides of the ball. It was, the record also indicates, easier to reach a level of consistency and ride the wave for a long period.

Still, the Steelers' streak of avoiding pitfalls against losing teams should not be diminished by the era in which it occurred, and it is particularly relevant in a 2002 campaign when it seems the lone constant is inconsistency. This is, indeed, The Year of the Ambush, and nearly every weekend manifests a graphic reminder of exactly what parity has wrought on the league.

The margin between franchises that are good and grotesque is significantly thinner now and, in an era that was purposely designed to avoid dynasties and promote mediocrity, the unthinkable upset has become obsolete. How else, for instance, to explain Green Bay's loss at Minnesota on Nov. 17? Or the Oakland Raiders' four-game losing streak or the once-resurgent New York Giants losing at Houston last Sunday afternoon?

Sidestepping the treacherous trap door, so routine for the Steelers nearly 30 years ago, has become a lost art form. It is a league now where a franchise's strengths and weaknesses must be re-evaluated every couple weeks, an NFL that sorely lacks a true powerhouse outfit, and a 2002 schedule where the final five weeks figure to produce even more upheaval.

"What you've got to do," said Tampa Bay strong safety John Lynch, "is try to avoid the traps."

An appropriate assessment since, in the jargon, there are certain matchups that have come to be known as "trap" games. There is no set definition for precisely what constitutes a "trap" game. But here's a loose explanation: A game in which a playoff contender faces a losing team, but one that still has some motivation for playing hard, and possesses some matchup advantages.

	“	In this league, I don't believe your players take another team lightly. I know people don't believe that but I do. Especially this year, it's just a matter of how you're playing, and if you aren't playing well, you'll get beat. ”
		— Herm Edwards, Jets coach

Last weekend featured at least two "trap" games -- Tennessee at Baltimore and New York at Houston -- and in both cases the underdog prevailed. The upsets produced plenty of head-scratching around the league, but they really should not have, since the streaking Titans and Giants both seemed overripe for an outing where they underachieved.

And there were these elements: The underdog Ravens are still playing tough on defense and had held Tennessee tailback Eddie George, the centerpiece of the Titans offense, under 100 yards in eight straight previous games. The expansion Texans continue to play hard in their debut season, have young guys attempting to establish their future viability in the NFL, and on paper were not dramatically inferior to a Giants team whose record appears to be better than its assembled talent base.

One defensive coordinator for an NFC team likened a "trap" game to the theory of the so-called "perfect storm," but that is hyperbole this year, since the elements for upset are present almost every weekend. It does not take nearly as much, particularly given the leavening of the talent distribution that has taken place under free agency and the salary cap, to create the kind of environment required for a "trap" game. And this season certainly has reinforced that notion.

Entering this week's schedule, there are 10 franchises either leading in their division or tied for first place. Only two of the first-place teams have been able to avoid dropping at least one game to a club with a losing record at the time of their meeting. In all but two weekends this year, there has been at least one game in which a team with a poorer record than its opponent was victorious. Not all such contests were "trap" games but many certainly fit the qualifications.

"In this league," said New York Jets coach Herm Edwards, "I don't believe your players take another team lightly. I know people don't believe that but I do. Especially this year, it's just a matter of how you're playing, and if you aren't playing well, you'll get beat."

Given the relative parity of rosters, the fact that not many teams possess more than a few "difference makers," coaches agree there is no formula for avoiding the kinds of upsets that have marked this season. A few suggested that, if you can run the football, stop the run and avoid turnovers, that will be good enough to win most weeks.

That's probably as close as teams can come anymore to a solid blueprint. But there are still pitfalls and pratfalls lurking in the schedule and that will become painfully evident as the playoff stretch run continues. In a league that has essentially legislated against dynasties, has systematically expunged the powerhouse teams, the "trap" games are fairly predictable.

"You just hope," said Green Bay safety Darren Sharper, "to stay out of the trap as long as you can."

Len Pasquarelli is a senior writer for ESPN.com.