One moment you think the Green Bay Packers are sitting pretty; the next, everything falls apart and the defending champion New York Giants make a statement.
But this is what we love about the NFL, isn't it? The unpredictability? The inner battles? The quarterback controversies?
Here's a look at some of the most important games of Week 13.
Minnesota Vikings (6-5) at Green Bay Packers (7-4)
Where: Lambeau Field, Green Bay, WI
When: Sunday, Dec. 2 at 1 p.m. ET
The Vikings are immersed in a wild-card race at the moment with the Packers, Seattle Seahawks (6-5) and Tampa Bay Buccaneers (6-5). They currently hold the No. 8 seed in the NFC, but a solid run down the stretch could vault them into the playoffs.
The Packers hold the NFC's No. 5 spot right now, but a 38-10 loss to the New York Giants last week hurt and they are certainly not in the clear. They are chasing the Chicago Bears (8-3) for the NFC North crown.
Green Bay looked bad in all phases against the Giants and facing Adrian Peterson is never fun. Second-year quarterback Christian Ponder will have to expose the Packers' pass defense in order for the Vikings to pull off the upset, though, and he got roughed up by the Bears last week.
Sunday: Pittsburgh Steelers (6-5) at Baltimore Ravens (9-2)
Where: M&T Bank Stadium, Baltimore, MD
When: Sunday, Dec. 2 at 4:25 p.m. ET
This AFC North clash seems to always be entertaining, no matter how each team is playing at the moment. In fact, just two weeks ago, the Ravens won a 13-10 nail-biter against the Steelers in Pittsburgh.
The Steelers, who currently trail the Ravens in the division and hold the No. 6 seed in the AFC, just lost an ugly game to the Cleveland Browns.
Baltimore has won four straight contests since the 43-13 embarrassment to the Houston Texans in Week 7.
Expect a defensive battle at M&T Bank Stadium on Sunday.
Monday: New York Giants (7-4) at Washington Redskins (5-6)
Where: FedEx Field, Landover, MD
When: Monday, Dec. 3 at 8:30 p.m. ET
After an ugly start to the season, the Redskins have bounced back behind rookie dual-threat quarterback Robert Griffin III, winning back-to-back games against the Philadelphia Eagles and the Dallas Cowboys.
All of a sudden, Washington has a glimmer of hope to make the playoffs, but everything must go right down the stretch.
The Giants won't be an easy opponent, however. They crushed the Packers last week, racking up 390 total yards on offense and sacking Aaron Rodgers five times. And Eli Manning just has that look in his eyes.
An interesting side note: The Giants have allowed 4.4 yards per carry this season (23rd in the NFL) and the Redskins love to run the pigskin with Griffin and rookie running back Alfred Morris.
The passing game has also looked much better for Washington in the past two weeks.