Defeat Ironhide inside the Conquest Pit and speak to Bookie Vel'jen for a reward.
So you're interested in the fights, eh? Well, Krenna has outlawed pit-fighting for all enlisted combatants. But you, my friend, are technically a free agent and are not included in this prohibition.
Nice loophole, eh?
Anyway, if you're interested I can start you off with something easy, a measly bear. I'll even let you bring friends along!