Gamereactor have posted a hands-on preview of Call of Duty: Black Ops and writes:
"Naturally there are new game modes. The most entertaining one I got to try was the Wager Match mode Gunslinger. The objective is to kill an enemy with each of the 20 weapons available in the game. After each kill your weapon is automatically switched for a new one. It gives the action a lot of variation, and forces you to change strategies on the fly. You have to be very vigilant, because if you get killed you lose a level and you're forced to register another kill with a previous weapon."