It's the final episode of "The Amazing Race," four teams remain and, if the previews are a reliable indication, we have the delicious spectacle of "bog snorkeling" ahead of us. That should be an Olympic sport, don't you think?

As the episode begins, the final foursome are headed for Belfast via ferry and then by car to the bog at Peatlands Park.

Road block: Bog snorkel

There, one member of each team must "race in the murky marsh," Phil explains from the comfort of a cozy pub. Racers will have to don wetsuits, snorkels and flippers, do a cannonball entry into a muddy bog and then complete a 100-yard swim in under 4 minutes. OMG, this is an awesome sport.

Anthony knocks it out of the park, er, bog with a time of 2:18. Katie goes flying down the reed-lined trench, as Max voice-overs, "She likes tanning on the beach. Not so much swimming. Not so much swimming in bog water."

Soon Mona, the roller derby mom, is flailing in the water, moaning and shrieking, "Where am I?" And poor Jen, the country singer, gets confused, jumps back into the trench on the wrong side and promptly gets stuck in the mud. On the second attempt, an anxiety attack sidelines her. She finally finishes on the third try.

Detour: Tray it or spray it

The next clue waits at a giant ring, held aloft by a giant sculpture and teams have two choices. "Spray it" requires teams to finish spray-painting a piece of graffiti art, using a photo for guidance.

In "tray it," teams must descend into the dry dock where the Titanic was built and where a commemorative dinner is being served in a grand tent. There, one member of each team must prep the dishes for a five-course dinner, based on what was actually served in the ship's first class dining room, while his partner serves. The catch? It's a five-course meal but the seating chart only shows two dishes per guest -- for the two courses where people had a choice about what to order.

Teams will have to use both the big menu and the seating chart to figure out who gets what, and first up is oysters for all. Katie figures it out, loads up a tray of oysters and goes pelting down several staircases and across the dry dock to deliver them. Max races off with the second course: consomme for some guests, cream of barley soup for others, depending on Katie's interpretation of the chart.

"It was much more beneficial if I did the bowl work and she did the thinking," Max says.

Bates and Anthony have to start over, but they figure it out pretty quickly, despite Anthony managing to drop an entire tray of dishes and general confusion about the color of chartreuse. Green, people, green!

But even after three, four, seven attempts, the hockey moms still have not figured out that there's a first course. Meanwhile, the country singers -- who took a major accidental detour -- head for the graffiti task and start spray-painting.

The pit stop

The newlyweds are first to arrive at the pit stop at Belfast's famous Ulster Hall, with hockey bros Bates and Anthony just behind.

"I have this recurring dream," Max tells Phil, "running around the corner and knowing we're first."

"I have that same one," Bates says. "But I run in front of them."

The roller derby moms are team three, and the country singers -- and their adorable knitted hats -- are out.

The finale at last

It's show time and the last three teams are headed for London and then Washington, D.C. to the spot where Martin Luther King, Jr. gave his "I Have a Dream" speech, the Lincoln Memorial. From there they'll head to 1100 Pennsylvania to get their picture taken with the president.

"Are you telling me the President of the United States is going to give us our next clue?" Max marvels.

Um, guys, the White House is at 1600 Pennsylvania -- and 1100 is a photo shop. The roller derby moms, however, are not paying attention to addresses. They're heading straight to the White House, which promises to be all kinds of fun, until a Secret Service agent -- a real one -- redirects them. Darn.

Roadblock: Secret agents

Next up: the Tidal Basin, where teams must find a marked town car, knock on the window three times and receive a briefcase. Ooo, how CIAish! They'll have to go through 50 trenchcoat-clad secret agents to find the one who accepts their password -- the cherry blossoms being beautiful in April or not being dressed for the weather -- and exchange briefcases. Love it.

The secret combination to open the new briefcase is the order they finished in New Zealand, Indonesia and Vietnam. Bates and Anthony kept notes throughout the race, just in case, and Bates pops his case quickly. Soon the brothers are headed for the home of the Nats, DC's major league baseball team, where a truly funny challenge awaits. One teammate must fly overhead on a zip line, lobbing a baseball, while the other, dressed like a giant baseball, waits below to catch it. More mascots bobble around, offering encouragement.

The brothers polish off the task fairly quickly and soon are headed to Hains Point. It takes the newlyweds considerably longer. And the Amazing editors have given the roller derby moms a "Ride of the Valkyries" soundtrack that adds considerable amusement.

The finish line

There's one last challenge -- the memory task. This time it involves an enormous cage of blowup globes, each marked with a specific country. One teammate goes into the giant ball pit -- "It was like I was 10 years old again," Anthony says, disappearing in a sea of blue and green balls -- then lobs globes, marked with the countries visited, to his partner, who must place them in the correct order.

First to the finish line at Mount Vernon -- and the winners of the million dollar prize -- are Bates and Anthony, followed by the newlyweds and then the roller derby moms.

All right, amazing viewers, what did you think? Gratifying ending? Did the right people win?