A contract is a contract. You signed it you have to honour it, otherwise you'll face the consequences. How much does it cost to break the contract? Can you gather a few colleagues and negotiate a breakaway deal? The boss will be afraid if there's mass resignation. If there's wrong doing on the boss's part, you can use it as bullets during negotiation.

Does the contract say anything about the scenario if you are sacked? if you don't have to pay a penalty when you are fired, you can do such a lousy job and piss you boss off every day till he willingly sacks you.