As anyone who plays Call of Duty knows, the series' true bread and butter is its multiplayer component. With a single-player offering that rarely spans more than eight hours, it's up to the multiplayer to extend the life of each title. Call of Duty: Black Ops , much like Modern Warfare 2 before it, contains more multiplayer content than should be allowed by law. There are challenges, most of the modes that you know and love from past CODs, and a little something new called Wager Matches.

Wager Matches allow you to bet your all-important COD Points (the game's currency that's awarded when you level up) on the upcoming match. If you finish in the top three of six participants, you'll be "in the money." Finish outside the top three and your buy-in (the money all players need to spend to start playing) goes bye-bye.

Fueling the new Wager Matches are some new multiplayer modes and Combat Training, a feature that allows you and a buddy to play against bots to sharpen your skills. Here's a quick look at our favorite Wager Match modes and why they're so damn cool.

One+in+the+Chamber

What It Is: Much like it sounds, you have one bullet left in your semi-automatic pistol. If you're lucky enough to shoot an enemy (anywhere), he'll die instantly and you'll get another bullet. Miss and you're left with only a knife.

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Why It's Awesome: It's a lot like Golden Gun from GoldenEye, but the tension is much higher since you have only one bullet. The feeling of walking up to two enemies who've spent their single bullet and have resorted to a knife fight, pulling out your gun and capping them both is tough to beat. Same goes for a last-ditch dive effort that leads to you stabbing your opponent's ankle. I call it the "action dive."

Gun+Game

What It Is: There are 20 levels to work your way through. For each kill you get, your weapon changes and you move to the next level. You start with pistols, work your way to submachine guns and assault rifles, and finish with rocket launchers, the crossbow and finally, the ballistic knife (it's a bell curve that starts hard and ends hard). If you get stabbed, you move back a level.

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Why It's Awesome: The strategy and skill required to win a Gun Game match is unprecedented in Call of Duty. You have to be able to use virtually any weapon in the game, and use it well if you want to win. Gun Game will be the mode that's the truest test of someone's pure FPS skill.

Sharpshooter

What It Is: Everyone starts the game with the same random weapon and that weapon rotates every 45 seconds. You could get double automatic pistols, or you could get a ballistic knife. But hey, at least everyone is in the same boat. Perks are handed out as you collect kills.

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Why It's Awesome: Yet another test of someone's true skill, Sharpshooter forces you outside of your comfort zone as you have to contend with a randomly generated armament. That would be fine, but the fact that you get some pretty impressive perks (and pro perks) as your kills begin to stack up could give you the upper-hand needed to break into the coveted top three.

Combat+Training

What It Is: The training mode that you've always wanted is finally here. You and a friend can hop online (or play via split-screen) and take on a team of enemy bots and earn those valuable COD Points while you're at it. Even though the COD Points don't count to your tally in competitive multiplayer, it still allows you to test the waters for sculpting your character.

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Why It's Awesome: If you're like me and you aren't the biggest fan of hopping online and getting your ass handed to you, Combat Training is the perfect escape. The fact that you can tune the AI of your enemies to any of the game's difficulty levels and hop into any of the many multiplayer maps is just icing on the cake.

Stay tuned to IGN.com for our official Call of Duty: Black Ops Review on Tuesday, November 9 at 12:01 AM Pacific Time.