Jason Kottke links to these ESPN highlights from the 2011 and 2012 combat juggling finals. Yes, it appears to be real:
Some more information from Wikipedia: "Combat or gladiator is a game played by jugglers. In its most typical form, a number of players juggle three clubs each, attempting to interfere with other players' juggling, with the winner being the last to remain juggling three clubs — not necessarily those they started with."
- Moving face-to-face with an opponent so the opponent gets confused about which clubs to catch. (Only works on novice players.)
- Throwing one club high, and using the time to wave a hand or club in front of an opponent.
- Turning around and backing into the opponent's clubs.
- Grabbing an opponent's club out of the air, and either dropping one of your own clubs, or continuing with four clubs.