Contracts

Contracts are a new feature in Call of Duty: Black Ops. They will replace the old challenge system.

Mechanics
Contracts are available to purchase will CoD Points. Different contracts will have different goals, such as achieving a certain number of killstreak rewards. Completing a contract will yield more CoD Points than the player paid for the contract itself. The higher difficulty of the contract, the higher payout upon completion. This may have also been a way to prevent hacks such as 10th Prestige lobbies.